Ok, here we go:
Vox Tonelab:
Price: List price 600usd but 299.95 usd from ZZsounds seems to be the current cheapest price.
Unique features: It does use a 12ax7 tube for its fantastic valve reactor technology.
Why this is the best unit today: It simply creates awesome emulations of the most sought after classic tube amps, anything from twangin´tweed to screaming Marshall solos
Also, the very amp-like user interface makes this modeler a breeze even for the non-techie guitarist, there is no hidden sub-menus at all.
Whats bad with this unit:
No solid state modeling (I´m not joking, some of use actually like that!! )
Some of the built in pedal effects are average, especially the acoustic sim & compressor.