I am just about to place an order on HK for some Rhino 4c batteries for a pattern plane, based on the reviews and comments I have read here on RCU which have been generally positive.
The motor, SC, servos and hardware are all known brands, based on previous experience and personal preference for pattern flying.
I also fly IMAC (DA 100) and again I would not use HK equipment, apart from Rx and Ign lipo batteries.

However, as I fly Pattern and IMAC, I am probably not representative of the average club flyer. At my flying club, where the majority of members fly 40-60 sized sport planes and electrics, the move to HK is in full swing. In general the comments and experiences with HK have been very positive, especially amongst younger novice pilots on limited budgets.