I have not done any PvP, I don't do much PvP live either. Right now I think as we get better gear and get more crit things will feel much better. I think I have 12.5% or maybe 15% on the premaid. I have to use Inferno Blast a lot to get my Pyro proc, cuz it's a guaranteed instant crit.
I've been using Rune of Power, and for the lvl 100 I have tried mainly Meteor and Kindling. Kindling seems slightly better for Single target while Meteor seemed better for AoE. I actually did not try 5 target with Meteor that was with Kindling, but 3 target I was pulling the 17.5k with Meteor and the 14.5 with Kindling. Oh BTW that is an unglyphed IB. So the damage could be higher.
The Feel of it- Seems pretty straight forward. Kind of like Destro. Feels to me like I spam FB to much, I mean without Living bomb It would really pain me to play the spec. Without living bomb you would spam FB till you got a crit, then IB, Pyro, combustion, and then back to FB. At least with LB you get something else to try and keep up and have to watch.
That said you can Scorch like a mofo when you need to move and pretty much keep up your entire rotation you must replace FB with Scorch.
I really think Fire spec needs some thing to break up the FB spam more. But mind you this is only ilvl 591. Once you hit a higher ilvl you could be possibly doing a crap load of insta Pyro's. When I was doing AoE sometimes I would get something like this... LB, FB+crit, IB, pyro, combusition, IB, pyro, LB, FB+crit, IB, pyro. So it can get pretty crazy. Combustion resets IB. So you can get strings like FB+crit, IB, pyro, Combust, IB, pyro.
If they don't give us anything else like a *proc we could use FFB with* or something of that effect I am hoping that we have enough crit to get a lot of mixes of pyros. Because unlucky strings of FB spam really sucks and feels boring as can be. I wouldn't call it clunky as much as I would call it monotonous. When I used Meteor I used it right before Combustion, so it's not like that breaks it up either.
I have not tired the Prismatic crystal to much, I have seen a video though on some people pulling off some crazy AoE dps, though they say that it's untuned dps.