The consensus seems to be that the older stuff is decent, but the newer stuff is hit or miss. I can't speak for the newer stuff, but I have been very happy with my dusty old unit.
My retired DAW has a Delta-44. Bare bones, no pre, no frills, but rock solid. It is PCI. I can't speak for Win 7/8 driver support because that DAW is XP. Several posts back, somebody mentioned using a Delta 1010 on Win7 with no problems. So I would guess that the smaller PCI-based siblings in the Delta family would work just as well with the newer OS. If you can find an older unit, it might be worth investigating.
I'll probably never sell my 44 because it runs well on an old computer that has been relegated to jam party duty.