I have had both the First Sound and the Supratek, and ended up keeping the Supratek. The First Sound IS a very dynamic, "big" sounding preamp with the blackest background I have ever heard with any tube equipment. It is a great choice. I went with the Supratek because I thought it was also dynamic, and had a musicality that I have yet to hear matched by any preamp I've tried or heard. The best way I know to say it is that with my Supratek, I stopped listening for sonic attributes of the unit and couldn't help listening to the music. It has become the crown jewel in my system, and many others.
Oddly enough, I see that the very same unit that got all this started (the original unit that was so highly reviewed) is up for sale now for a cool $2100. If I were in the market for a preamp anywhere near this price range, I would jump all over that. A rare opportunity to get a discounted Syrah and not have to wait half a year or more.
I have no affiliation with the company or the seller of that used unit--just a very satisfied owner.