software

I'm starting my quest for 'the' tube amp and i've come across the randall MTS series. If you didn't know about these, the amps have modules you can buy (all tube) that emulate tons of classic boutique amps. This sounds great to me because i'm a huge fan of the flexability of modeling amps. On to the questions:
1. Has anyone tried one of these yet or any opinions?
2. Randall also offers the amp in a rack format. The power amp has 50w(6l6's) and 50w(E34l's) in stereo (you can adjust volume, presence, and density of each). I'm new to tube amps so can someone explain the differences between the sounds from these types of tubes?
3. Is this power amp idea (different tube types) good enough for someone to buy the rack gear instead of the head (the head is offered with either type but not both)?

Any other comments for Randall or tube amps are welcome.

1. Haven't tried one, but I do like the idea of preamp modules.

2. 6L6's will have a bit more low end and top end, and stay cleaner a bit longer than EL34's, while EL34's are a bit browner and softer and transition into breakup more smoothly than 6L6's. Try 'em both and see which you like better. It's like the difference between an old bassman and an old JTM 45.

3. stereo poweramp might be cool if you have a stereo cab or 2 cabs.