It's not that slow, but not as fast as other builds.
I have a level 75 bard/cleric w/ lvl 72 bard skills/70 cleric skills. It's pretty SP intense, though, so I would suggest farming.
Yep, the nukes are plenty fine, just kind of stinks until 60. You get one nuke and an AOE nuke before then. After 60, you get a nuke that hits 3 mobs. I can two-shot party ongs and three-shot champ pt ongs, and I am a hybrid with 5-6 levels of STR. Not bad for a support build.
PVP for me is slightly more difficult, but I can still kill fairly easily as long as I can survive a nuke. Again, due to my hybrid, this is more of a support character.
You will not suck at PvE or PvP

It's fun being able to play either bard or cleric. The only choice is what armor you want, LA or robe. LA makes you keep your cleric almost equal to your bard skills.