The problem for me is dialing that tone in consistently night after night. I'm good on the vintage channel, but haven't quite figured out that drive channel and I really think that's where the real magic with that head lies. That's where I like the V4B a bit more - super easy to dial in a great tone.
The two channels on the 100T/SB are very different, which might lend itself to some of the trouble. The vintage channel is a standard passive fender stack which will be a bit scooped. The modern channel is a transistor based active EQ which should be flatter at noon. If you're trying to get similar tones, the modern channel should be closer in response to the V4B EQ which is the standard ampeg james/bax with an active midrange, AFAIK.
I'd say get an SVT anyways, but given that I've got about 9 amps right now I'm probably the wrong person to take advice from
