Yawningdog
The best of those, by some margin, is the Flycoms.
I switched to them and they are a revellation. Very comfortable, draught free, excellent viz and the removal of virtually all outside noise thanks to the Peltor DNR hardware inside. The result is your RT will be crystal clear and you don't need the volume high to hear what's being said back (so good for your long term hearing ability).
I can't fault them and they are cheaper than most of the others on your list. Two helmets, the Icom adapter, power lead and the PTT will be less than £600.