Indeed window clings are better!
I had a sticker and it went on my glass..
good news - it came off easily
bad news - it started to peel after less than a year (sorry I can't keep my van in the garage.. too much crap! )LOL
but it definitely was noticeable and it did come off easily when it was peeling
so another vote for window clings! :) yep I still have my magnet!