Hey, I have an idea... why not support the great publication of Cyclocross magazine and pick up their back-issue #4 which has a great review of tubulars. Can I get a WASSUP for CX Magazine!!!
Partial sarcasm aside, Velonews did a review and comparison of the major brands, and you can easily find that by searching"cyclocross tire reviews"
My input - I raced two races on them (some came on a wheelset) and I hated them. I peeled them off, and they sat for a year until I gave them away to a newbie. Good tread design, but stiff and worthless casing. They now make a fancier high threadcount tubie that is supposedly better, but I'm never gonna buy them.
I agree that the tread design is good. I don't think the casing is so much stiffer than Grifos to warrant an extra $60 or so. I have a set of Grifos (260tpi) to compare the Vittorias (220tpi) with and found them more than acceptable. They are rated to 35psi but I've had pressure in the upper 20's with good results. Maybe I'm not sophisticated enough to notice the difference.
A bonus is that the sidewalls already seem well protected. I don't think they need additional sealant. I may be wrong; we'll see after a couple of more races.