I've never played the 6, but I have an SVT 4 Pro and it's amazing. I got it for something around $1000, and it was absolutely worth it. You can get a ton of different sounds from it, and it's easy to deal with. I only have two minor concerns about it that didn't matter until just recently. First, it's heavy. I play it through an Ampeg 410 HLF and they weigh almost the same...
My other problem is that it doesn't have a headphone jack. I usually play pretty late, and it's bothersome not to be able to use my headphones.
Neither of these are huge problems though, and can be worked around. They definitely wouldn't make me want to switch amps. You should probably try playing the both of them a bit more and see which you like best, and if it's worth it to spend the extra money. Either way you'll end up a pretty happy guy.