hey... this is in my lane!
As a qualified Air Defence Instructor in Gunnery, I can say that the ADATS stacks up very nicely. The EO package is pretty decent (FLIR and Low light TV), even by today's standard. The ADATS missile travels faster than Mach 3, so time the time of flight out to it's max range of about 8km is pretty short (something like 8 seconds IIRC). The guidance is via laser command, so no worries about bushes breaking the wire! The warhead is quite large (about 22lbs IIRC) and even though it is a shaped charge, something that large, hitting that damage is going to do alot of damage. I've seen video of T-72s being hit by ADATS missiles in Suffield and the results were definitely eye-popping.
Now to the drawbacks of ADATS: it has a high profile and high CofG, which has led to more than one flipped ADATS. It is a huge diesel hog- the APU will suck the tank dry every 8 hours. It was (in the 1996 timeframe, when I worked with it last) very maintenance intensive. Finally, the missiles cost $250K back in 1992 and Canada owns the entire world's supply of them (ie- not alot).
Kincanucks can probably give more recent info, as he is about to graduate from this year's IG course.