In my experience I've found the magnets sets to be the best out of the cheap plastics. I've gotten Star wars, and toy story and they are almost a perfect match to the real thing. But battle packs and the lego store volume packs (Not the minifigs, the five pack collection.)are horrible! Cheap, opaque, non clasping hands. Torso looks like it has a decal on it and not a print. Weapons are a darker shade, and very brittle. Arms rotate like crazy, legs wobble, hands can't turn. Mega Blocks are 10X better quality then that crud. *Rant over.*
Long story short the magnet packs are the best of a worser world. (Is that a word?) They look just like the real thing, but you can tell they arn't. (Missing neck print, and branding on right armpit.) They are a great way to get a fig you want, at a decent price, and are col. minifig quality.