There are a number of parameters in choosing an “electric” bowed instrument. The first thing to consider is the style of music and the kind of playing that you intend to use the instrument for.

Let me explain myself: to play rock music an electric acoustical instrument is not a necessity. It can even be counterproductive due to a typical acoustic phenomenon called “wolf tones” and resonating peaks generated by the soundboard. A “Solid Body” would be just fine due to its more linear tonal behavior.
On the other hand, for a musician playing Jazz or Classical music, the tone color, and the dynamics of the sound are fundamental. Therefore, these musicians are more willing to patiently wait for the fine-tuning of the instrument and the electronic set-up.
There is one main principle of every electrified instrument that most musicians are wary of. Whether it is
traditional or electric acoustical, it becomes a “new instrument” in every way when it is amplified – it is a new instrument with new characteristics and new issues.
This means that the parameters that functioned well for an instrument with “natural amplification” will have to be reviewed. Considering that “amplifying” sound requires technical skills even for “picking up” the sound, one must proceed with methodology having a clear idea of the results to be obtained, which means that the skill of the builder is fundamental.

It is commonly said that the middle road is pointless and that is definitely the case with Electronic set-up. We provide two valid approaches for taking the best advantage of so-called “electric” instruments.
First of all, we should eliminate any exaggerations (both in cutting things to a minimum and going overboard) in the electronic set-up.
Too minimal: a pick-up and a long cord. Simplicity is a value without a doubt, but if a large part of the sound depends on the quality and length of the cord (especially if the pick-up is a piezo) we risk falling prey to too many external variables (and there are already more than enough).
Too complex: several pick-ups, (which are similar between themselves) and various states of amplification with compressors, equalizers and active filters, etc. They are useful (if they are well managed). However, they go against the nature of the instruments that we are dealing with, because they create a really high risk of losing the “naturalness” of the sound (in an instrument that is already a synthesis).

We have identified two electronic set-ups to use as a reference.

Basic Set-up: simplicity is definitely an advantage and for that reason, a single pick-up (which intrinsically
provides better reliability and mental ease – important factors in making good music), and a buffer are included in the basic setup. It does not matter whether or not it has a volume control, the important thing is that it immediately adapts to impede and protect from any disturbances or absorption due to cords that are not in perfect shape. This kind of set-up would be fine for those who play exclusively pizzicato style: but musicians who use a bow have other requirements.
Complete Set-up: in this set-up, there are two pick-up points with different types of pick-up to avoid layering of the frequency response curve (creating damaging counter-phases). This means there are two different mixable timbres available for different needs (bow or pizzicato, solo or in a big band, the acoustics of a dry or a resonant room) without the use of active filters or various adjustments, which can severely decrease sound quality. Dual pick-ups adapt easily to audio systems and free you from total dependence on sound engineers!
It is evident that this plan requires a higher quality instrument because it is impossible to create a sound that doesnʼt exist!

Getting back to the primary parameters of choice: certainly, a decisive factor is the ease of transportability, especially for cellos and double basses. Once again, choosing the middle road is no benefit. Though they are more manageable, even an electric instrument will never be compact enough to transport and that extra centimeter almost always causes problems.
Always evaluate the total space required and the form of the case, which should not be round like a trunk, but thin and proportioned to fit anywhere.

Durability: traditional instruments may also be durable, but they require constant attention to prevent damage. With an electric instrument, it is fair to expect that this is not as much of an issue. Robustness refers not only to big dimensions but also to the fact that the instrument is not affected by small bumps, that it is easy to remount, and that it can be upgraded or repaired all over the world. It is not easy to judge the quality of an instrument, but it is worthwhile to fully evaluate these criteria before purchase to avoid future “surprises.”

Feeling: there are instruments that search out traditional forms and others that create new parameters. In any case, it is fundamental that there is total control of the instrument without having to hold it in an unnatural way which limits the musician’s ability. It is important to evaluate all of the arm and leg rests and/or consider the possibility of personalizing the instrument and it is better to choose components in wood than in plastic.

The most important factor for the best feeling (and we could dedicate an entire chapter to this) is the
Playability of the fingerboard.
The proper fine-tuning of the fingerboard is even more important than the quality of the wood used!
It is definitely more of a joy to play on beautiful African ebony, (black as night with almost invisible pores) than on a piece of painted beech wood. The higher elastic modulation of ebony provides a different frequency response than rosewood or many other less noble woods.
When evaluating an instrument, especially if it is in the low average price range, it is important to verify the proper level of the fingerboard, the correct spacing of the nut, the length of the strings, and the degree of curvature of the bridge.
There are double basses with large fingerboards made of good ebony that are flat and mounted on very high bridges to avoid the strings slapping the fingerboard. This means that your luthiery will have to intervene sooner or later to make it playable.
Normally, “electric” instruments have fewer problems with climatic variations and therefore bridge adjusters are not indispensable (they are an obstacle for transmitting the sound). However, if they are requested (to play different execution techniques for example), it is important to verify the slidability.

If the electric instrument is not destined for performance, but only for individual study, listening with headphones is indispensable to avoid disturbing others and for hearing all of the harmonics to control the intonation.
When used for individual study, the “naturalness” of the sound (but also the feeling of the bow on the strings) is decisive. What point is there in practicing with an “artificial” sound, if the reality of the classic instrument is entirely different later on? Some instruments sound very good in headphones, but this can also be due to the fact that the more strident harmonics have been cut, or even worse, that a reverb effect has been added which camouflages the reality of the sound.
A good method for judging the instrument is to play it and feel the reaction of the strings under the bow.

Let us consider the aspects of personal choice, which go beyond simply practical issues.
For string musicians who play with a bow, the electric instrument can be a “toy room” (a sort of mental space more than a physical one) where it is possible to develop one’s personal musical ideas both for recording and elaborating a sound or improvising in privacy – experimentation that is not necessarily part of one’s primary occupations – while listening with headphones.
In this case, I do not believe that there are rules in choosing, you have to follow your own personal instincts. The only thing to verify is that the instrument that you are about to purchase does not limit your ability.