i use the new zeagle FH7 and my buddy dives the zeagle FH6 and we dont have any problems. constantly down at 90 feet in mid 30 to 40 degree water all year long and they have surived ice dives also.
my buddies wife has zeagle envoy's and has not had a problem, and they are not enviromently sealed.
seams like most people are using atomics, apex, scubapro, and dive rite. as fdog said see what the shops near you sell and service. at the least it will be easy for you to get them serviced.
I'm curious, what is the differnece in the FH7 and FH6?