Yeah, ring of valor is hit or miss for me -- if the other team has a melee cleave and they're geared its usually GG for me.

There's two strategies -- popping hero just before hitting the ground and blowing up someone (ret pally shamans are the best, followed by warriors). OR -- ghost wolf and immediately run behind the rear pillar -- I've had about the same success and failure with either so I can't really say which way is the better way to go, all though the immediately nuke seems to work slightly better if you target a melee or someone unlikely to start off the match running behind the pillar.

However mages love to run in, frost nova and blink behind you while you're stuck and rogues shadow fury while the warrior comes in blade storms.

Did I mention kill the shaman?