I have been flying this bird since 2007 now and I really like it!
Frozen brakes: I never had this, although I have been Moscow in snow storms etc.. there is a procedure for taxiing and taking off in snow, slush and standing water (with cold temperatures). You just heat up the brakes before takeoff by applying them a couple of times. There is a temperature sensor that will show you if they are still below 0 degrees or if they are okay.
APU oil leaks: in my opinion the main problem is the angle in which the APU has been installed. Leaking oil runs back to the core where the bleed air valve is and it can get sucked in then. You normally notice this at the end of a long descent when you advance the thrust again. "Dirty socks" smell...
Water system: I always stick to the draining procedure and it still breaks every now and then. The last few times the t-handle (and the valve that it moves) were broken. The good thing is: in such a case you can still refill the system from inside, there is a gravity filling system.
Landing performance: in my opinion it is very good. You just need to stick to the limits, fly the speed and don't flare too much - the brakes and reverse are efficient. In Cannes I can easily bring it to a
smooth stop half-way down the runway, although CL300 hates me for it
If I had the money and had to choose, I'd go for a Falcon!