I've seen a few people ask about this screen protector for the Droid, so, being I have one, I thought I'd provide my opinion on it.
Seidio's Ultimate Screen Guard has one major advantage over other screen protectors, in my opinion, and that's this... you install it without ANY water or soapy liquid being applied to your devices screen, and without any adhesive.
The Ultimate Screen Guard is applied using static cling... you peel off the backing, line up the screen guard so that it's perfectly lined up with your device's screen, then use a firm plastic card to roll in in place. It stays on firmly.
The USG also has the advantage of no orange peel effect, a problem with Invisible Shield and some other screen protectors, where, under certain lighting conditions, you see ripples on the screen guard, what looks like the pattern you might find in an orange peel. The USG is clear as glass, and nearly invisible once applied!
I've also found that it doesn't interfere with the touch sensitivity of the device, either. Scrolling, tapping, everything works as well as it did with a naked Droid.
If there is one negative I can give to the USG, it's that it shows smudges and finger prints much easier, and more prevalent than on a naked Droid. Furthermore, while with the Droid's glass I can easily swipe the screen against my pants leg or against my t-shirt, and it'll appear completely clean, the USG doesn't clear off smudges quite as easily. Wipe it with a cloth, and you'll still see smudge marks.
I find I need to use a micro fiber cloth, spray it with Monster Screen Clean or some other screen cleaning liquid, wipe the screen, then use a dry portion of the cloth to dry the screen, to get it sparklingly clean.
That being said, if you're worried about scratches on your Droid's screen (there seems to be some dispute as to whether or not the Droid's glass can even be scratched, but I've read at least two posts from people who swear they have small scratches on their screens), the USG seems to be one of the best options available!
It's also nice to know that, if and when you decide to remove the USG, there won't be any sticky mess you'll need to try to remove from the screen itself.