fujitsu
Fujitsu seems to be overlooked a lot, I was going over their site a few days ago and was quite surprised to see this monster array which at least on paper seems on par with many features that other high end vendors offer, and one or two unique ones.
http://solutions.us.fujitsu.com/downloads/DS_Eternus8000.pdf
Up to 8 controllers, and 2700 disks
The Cyclic cache mirroring is pretty unique I think. I sent a note to my 3PAR SE who was pretty impressed as well though says they don't encounter Fujitsu much here in the US, must be more popular in Europe. With such an impressive system I'm surprised they don't push it more in the US.
It doesn't appear that they do block based virtualization like 3PAR or Compellent. Also I don't see an indication of supporting hyper-dense drive enclosures. 3PAR's S/T class support 40 drives in 4U. Providing such density is fairly complicated as you need to have software that can automatically lay data out in a way to handle multiple drive failures(to replace a drive in a 3PAR S/T class you must remove 4 drives). Another big vendor that was pitching their stuff to me said they were going to go hyper-dense this year as well though I haven't seen it happen yet.
Also I think the USP (non USP-V) is also a virtualizing storage controller. the USP-V is just the low end model of it.
I think the V-MAX would of been more impressive had they scaled the architecture down to some extent so it's more affordable. Maybe they will do that in the future. I saw a price somewhere listing a V-MAX entry level system at $250,000 with no disks, the article didn't mention what it included exactly for that price. I suspect their interconnect is what drives a lot of the price of the controllers.
When 3PAR announced their first array back in 2002 it was advertised as something similar - 8 controllers, 2560 drives, 192 fiber ports, 28 gigabytes/second interconnect on the 8-node box. Entry level pricing starting at $100k - http://www.3par.com/news_events/press_releases/20020610.html