We've had some issues with Niles having problems with some Rotel commands and Sharp projectors. Probably the biggest headache is developing a usable IR library. The learning ability of their IR capture system is moody at best, and sometimes they just flat out don't do what the software says they should be doing and you have to get creative to get it to control things properly. Having said that, once you get one up and running, they work pretty good and experience a minimal number of crashes.
The only other thing to be aware of is that they don't like to be dropped. the weight of 3 D batteries tends to make the fiber optic connections inside the remote unit break after a minmal amount of abuse. Fortunately, Niles has replaced every remote we have ever sent to them at N/C regardless of age.