I have a Tab X and I love it. (Disclaimer: I've only had it for about a month so far)
I first ventured into electronic music stands about 10 or 12 years ago, but because a lot of my playing is outside I very quickly found that LCD/TFT displays were absolutely useless, battery life was ridiculously short, and gave up on it. More recent tablets from pretty much all manufacturers seem have much brighter displays that can often be made to work, but the brightness still has to be turned up so high that the battery still goes flat pretty quickly. Of course, this can be overcome if you purchase a backup, external auxiliary battery pack/charger. I did this "just in case" but have never needed it... I can play several back to back 2 plus hour gigs without recharging.
A friend of mine actually reverted to paper from her iPad for outdoor gigs because between the brightness being way up, and the heat of the day her iPad would shut down due to overheating. I assume to prevent thermal runaway in the battery.
On the other hand, my TabX is GREAT in bright light. I don't miss any of the niceties Mike mentioned as being unavailable or unwise to use with an e-ink device. I have a cheap, Amazon bluetooth pedal and it works fine. Response time is good.
The front lights work well, and having separate , controllable "cold" and "warm" lighting makes adjusting visibility in marginal light a snack.
The battery life is excellent.
About the only thing I miss is a camera. I didn't notice one was missing from the specs prior to purchase, but understand why one isn't included - can't display colour photos anyway - but it also means I can't grab a quick photo of a chart and display it on the tablet. Colour for highlighting would be nice too.
Make sure you buy a cover for it... Oh yes, there is no metal strip for the magnet in the stylus to stick to, either on the tablet or the cover. I fixed that by cutting up a steel tin (actually it was an empty aerosol can) and fashioning a couple of strips that I glued to the cover - make sure to eliminate any sharp edges or corners if you decide to try this. Mine are about 50mm by 16mm, bent along the long axis to conform to the curve of the device and cover, corners rounded over, painted black and glued to the cover, one outside and one inside where the cover folds back on itself when open.
Currently I use mine by sitting it on a music stand rather than having a tablet specific holder (the magnets in the cover tend to hold it in position on the stand too - a serendipitous bonus). This is primarily because I like the convenience of places to put my spray bottle, or valve oil bottle*, and other bibs and bobs I like access to when I'm playing. A bonus is that because my stands are steel, the stylus also sticks to them.
* Depending of what instrument I'm playing. All my music stands have double shelves too.
In closing, if you never play outside, then I suspect a colour display on a non e-ink device would be more to your liking, especially if you use a "highlighter". If necessary the shorter battery life can easily be overcome by using either a charger or external battery pack while you're playing or between sets.
BUT if you play outside, then the E-Ink display is unbeatable IMHO.
PS - Onyx recently released a smaller (10.1" ?) colour e-ink device, and I suspect there will be a colour TabX (or equivalent 13.3" device) in the relatively near future. I also suspect it will be a premium price.
I first ventured into electronic music stands about 10 or 12 years ago, but because a lot of my playing is outside I very quickly found that LCD/TFT displays were absolutely useless, battery life was ridiculously short, and gave up on it. More recent tablets from pretty much all manufacturers seem have much brighter displays that can often be made to work, but the brightness still has to be turned up so high that the battery still goes flat pretty quickly. Of course, this can be overcome if you purchase a backup, external auxiliary battery pack/charger. I did this "just in case" but have never needed it... I can play several back to back 2 plus hour gigs without recharging.
A friend of mine actually reverted to paper from her iPad for outdoor gigs because between the brightness being way up, and the heat of the day her iPad would shut down due to overheating. I assume to prevent thermal runaway in the battery.
On the other hand, my TabX is GREAT in bright light. I don't miss any of the niceties Mike mentioned as being unavailable or unwise to use with an e-ink device. I have a cheap, Amazon bluetooth pedal and it works fine. Response time is good.
The front lights work well, and having separate , controllable "cold" and "warm" lighting makes adjusting visibility in marginal light a snack.
The battery life is excellent.
About the only thing I miss is a camera. I didn't notice one was missing from the specs prior to purchase, but understand why one isn't included - can't display colour photos anyway - but it also means I can't grab a quick photo of a chart and display it on the tablet. Colour for highlighting would be nice too.
Make sure you buy a cover for it... Oh yes, there is no metal strip for the magnet in the stylus to stick to, either on the tablet or the cover. I fixed that by cutting up a steel tin (actually it was an empty aerosol can) and fashioning a couple of strips that I glued to the cover - make sure to eliminate any sharp edges or corners if you decide to try this. Mine are about 50mm by 16mm, bent along the long axis to conform to the curve of the device and cover, corners rounded over, painted black and glued to the cover, one outside and one inside where the cover folds back on itself when open.
Currently I use mine by sitting it on a music stand rather than having a tablet specific holder (the magnets in the cover tend to hold it in position on the stand too - a serendipitous bonus). This is primarily because I like the convenience of places to put my spray bottle, or valve oil bottle*, and other bibs and bobs I like access to when I'm playing. A bonus is that because my stands are steel, the stylus also sticks to them.
* Depending of what instrument I'm playing. All my music stands have double shelves too.
In closing, if you never play outside, then I suspect a colour display on a non e-ink device would be more to your liking, especially if you use a "highlighter". If necessary the shorter battery life can easily be overcome by using either a charger or external battery pack while you're playing or between sets.
BUT if you play outside, then the E-Ink display is unbeatable IMHO.
PS - Onyx recently released a smaller (10.1" ?) colour e-ink device, and I suspect there will be a colour TabX (or equivalent 13.3" device) in the relatively near future. I also suspect it will be a premium price.
You're only paranoid if you're wrong 
I'm using an Onyx Boox Tab X, and play low brass: mainly 'Bone and Tuba