Which head is best for me?

When I was originally considering buying a new head, I had the Carvin B1500 in mind, but after reading all the hype about the new Genz Benz Shuttle 6.0 on here I kinda flip flopped.

I do realize that these two amps are two completely different beasts, and I am still waiting on a 6.0 to come into the music shop so I can test it. The problem is that I won't be able to check out the B1500 without actually purchasing it. I don't want to make the wrong decision so I am wondering what you guys would suggest, or if there is an obvious answer for my style of music and bass playing.

I am in a pretty loud rock band (sounds like a mix between Switchfoot & Relient K) and we play at pretty large venues up to 500 people. I play mostly finger style but there is some slap in the songs, but I want it to excel at both. The sound I'm looking for is that loud chest thumpin clean with a little grit.

Weight really isn't much of a factor, I'm 19, but I would not mind a lighter rig.

Any insight would be appreciated!