I'll second the cpu requirements, although they're experimenting with gpu encoding finally, might be interesting to see how the new VDI xeon's work when they get that finalizedI use BI. Reasonably happy.
Likes: Rock solid, stable, reasonably full feature set, decent mobile app support.
Dislikes: I generally hate Windows, its a CPU pig (yes - you can tune it - but there are plenty of commercial examples of doing similar work with lighter CPU load).
On the balance, as far as I have found, there is actually nothing better on the market for the price.
Like I said in my comment - there are ways to tune it. But frankly you shouldn't have to - the work being done really doesn't require as much CPU as BI uses to do it.The key to CPU performance is to use the cameras to show the overlays, and not use the overlays inside of BlueIris itself, that way it doesn't have to encode. Once you remove the encoding the CPU usage is very low.