I'd avoid testors like the plague... Their stuff's way overpriced.
Testors stuff is, if I'm not mistaken, water-transfer decal paper... It's better IMO than messing with stickers personally, but it's a little more difficult to work with since you have to seal them and things to keep them from bleeding and whatnot.
There's cheaper places to get water-transfer decal paper though, no doubt. Micro Mark carries it cheaper than Testors little kit...