I tried JPH from the very moment it landed!. It is not a keeper. I've gone back to SlimJM8/Voodoo because of :-
1) JPH is laggy (compared to JM8)
2) The Phone does freeze occasionally ( don't tell me wipe etc!, I've done the cache/data wipe + internal sd card format + repartition etc.. so that no traces of old stuff remained). Still JPH is unstable.
3) The Exchange email is buggy. The fonts are too big for my eyes. And.... would you believe it?! - it cannot send replies to any emails!! LOL
4) I love the the Voodoo brightness fix because I read the kindle books on it in the night. The default lowest brightness setting is still too bright. Voodoo fix for froyo would arrive only if Samsung releases the sources under GPL (or someone find a way to patch the stock kernel with voodoo).
Despite the claims by many that this IS almost the final froyo firmware for SGS from Samsung - I strongly believe - it is NOT. This will not even pass a single stage in the acceptance tests.
My take -> Stay away from JPH. Wait for the official froyo build, which will land in a few days.
[ On the Positive side]
Google voice actions works pretty well with Indian accent english!. You get most of the Froyo goodness in JPH. To offset the above issues you can:-
1) Try One-Click-LagFix on JPH. That may help speed it up.
2) Use Touchdown / RoadSync as alternate Exchange clients
3) Use couple of matte finish Screen protectors on your SGS to reduce the brightness. OR buy Rayban sunglasses to read @night