The seaview stuff is really awesome, you spray it on and apply the background. It's not messy, and just smooth out all the bubbles. I think it's pretty easy to remove the background, and to re-use (I have a friend who uses, but I have not tried to reuse).
I used to apply all my backgrounds with regular ol' vaseline. I know it may sound wierd, but if you put it on the glass, apply the background and use a card to smooth it out, and remove bubbles it'll be stuck there.. it can be a bit messy but I love the end result. I just taped my background on my viv for now... Using Seaview or Vaseline will make your background POP - it makes it look like it's part of the glass instead of filtering through it....