I've not heard of "half and half", but having used all styles over the past 30 years, I know it isn't a horse collar and it isn't a wing, so it can only be describing the wrap-around of a classical (old style) jacket.
I have a KnightHawk and I know that it can't be this: it's a pure back-inflate wing configuration. In fact, I'm just wrapping up a test of its replacement, and my KnightHawk is going to be put up for sale.
For brisk UK diving and some trips, I'd expect that you would want something in the 34+lb lift range, maybe doubles capable, yet still ok with a thin wetsuit too. This might describe what I've just put 20 test dives on, namely a ScubaPro Glide Pro. It's a real jacket, so my "face down" issues with end-of-dive floats with my heavy UW camera are finally just about over, and it is technically doubles-capable, although scubapro's website does a poor job docenting this.
Everyone is going to have their own list of priorities for what is their ideal BC. For me, the end-of-dive surface float is a Safety issue and priority #1. Comfort is somewhat important, but do keep in mind that any thickness of wetsuit will provide some padding for comfort (and the stuff is mostly weightless underwater)...as such for me, key features on the BC itself ccome in at #2, which includes trim pockets and storage pockets (the Glide Pro has huge pockets...my KnightHawk is a bad joke). Personally, I don't use the weight integration (quick release) pockets at all - a std weight belt lets me put my waist weights in the small of my back for better ssurface float trim. If I were to keep my KnightHawk, I'd adapt them for emergency type items, such as a SMB.
Hope this helps...
-hh
