I bought a 8.2 H2 recently as I was using the NP V8's previously. Wanted something a bit bigger than my 7.5 V8 and it fitted on my existing 460 mast.
Did not consider any RS Slaloms as I only had an X6 mast and an alloy boom. I am more recreational than racing. Told the RS's prefer the X9 mast.
Very happy with the H2 which is not a "light wind sail" (that's the Helium) as someone said earlier. Its the new version of the V8's.
A piece of cake to rig and very light for its size. Only 2 cams. RS's can be tricky and do weigh a tad more. If you want max performance go the RS, if you are after an easier to rig sail that is almost as good but is lighter, go the H2.
Now I have three sails that go with the one board, mast and boom combination. Happy.