I purchased this one recently and have used it for some time in my home recording studio. So far, I'm very happy with it! It has no special features such as additional inputs so that musicians can have their own mix, but I was not looking for that. It does however have balanced stereo outputs so you can daisy-chain several units, or send the sound to monitors. It also has a button to turn off that monitor sound, which I use a lot.
Good things: the sound quality is real good and it is loud. I've used it with cheap Sennheiser phones and really expensive Audio-Technicas, as well as small in-ear phones and ithey all work great. It has no special features, which makes it extremely simple to understand and handle (power on - connect input - connect phones - turn on volume). The build quality seems good; solid aluminum (I guess?) case and steady knobs and sockets. At least it FEELS like solid quality. Time will tell if the electronics will last as long as I expect the casing will do. Also, the power chord is long, which comes in very handy when you need to move the amp around close to musicians. Last, it has a small hole on the bottom side and a screw that fits the hole - hence it can be mounted to a stand, which is not a bad idea, although I don't think I'll be using that feature.
Cons: only one thing really annoys me - the on/off switch is located on the power chord, around 5 cm from the actual unit. Need I say that it's connected to the back side? When placing the amp near musicians, perhaps on a chair, this is no problem. Often though I will place the amp on a shelf by my mixer/workstation, and turning the unit on and off is just really tricky with all the cables running on the backside of a studio rack. I know, maybe this is a very small thing to have an issue with, but if you plan to use this mounted in a rack, be aware that you'll have to turn it in by connecting the power cord to the wall socket.
So, apart from one tiny thing, I have been very pleased with this little unit - sound, quality, simplicity. If it broke, I would probably get a new one.