I have several Artec's and so far, they have been great. There is one simple one, with only a Volume and Tone that might be nice, although a bass control might be very useful.
Depending on the type of piezos, you will need an input impedance of 1meg to 10 meg. The higher you go, the more of the natural bass, and full tone can be derived from the piezos. However, you may not want full response, as the low end may put out too much body noise.
A simple buffer, Jfet, Mosfet, or op amp can be built easily for under $10. Endpin jacks are pretty reliable, but they do fail far more and faster than standard Switchcrafts.
The Artec will likely do the job just fine. Adding a volume control will require modifying the circuitry as the volume has to come after the preamp, so the connection to the Tip would need to be broken, and the volume wired there. (25k or 50k audio taper.)
Some preamps shape the sound, and usually for the undersaddle pickups. I don't think the Artec does, as it is also used for their magnetic pickup and their microphone.
If a preamp or buffer is used, and you want to mix the signals with magnetic pickups, there are other consideration. With passive magnetic pickups, you will need to add a buffer to them as well, with 10 megs for the piezo buffer and 1meg for the magnetic pickups. If the pickups are active, or you have a preamp, the piezo buffer/preamp can be mixed with the output of the magnetics low impedance output or the preamps low impedance output.
If you will to have a blend between the piezo and magnetic pickups (if they are active) a 25k or 50k blend, like the one for EMG's will work. If the magnetic pickups are passive, you will need a buffer between the pickups and blend.
I'd like to know more about your bass. If you don't like the Artec EPP, the other endpin preamps will not offer much more, other than volume and tone controls and maybe a little shaping, if any feature that.