imo prot is so much more viable, the damage isn't as bursty, but you can bring so much more to a team.
3sec silence every 10seconds straight into a 5sec stun is perfect. Also, you don't have to choose whether you want to spend your holy points on damage or survivabilty, it's saved for those heals! :]
+ you get like an extra 500 hp.. more armour.. etc etc etc. As a prot paladin, the only classes i find hard are arcane mages because their blanket 3sec silence = nasty, and you can't outrange dat arcane barrage!
oh, and the prot talent reduces the cd on your HoJ by 10secs.. which is always helpful.