I have used a number of brands....
bondo is a name brand, body filler is the product....I've used evercoat, bondo, and some usc brand....honestly they all seem about the same to me...it's how you use it that seems to make the difference...how you mix it, how much hardner, how heavy you put it on and how long you wait before you try to cheese grate it / level it before it dries completely...if you sand too soon it clogs the paper, if you wait too long to knock down the high spots it's tough to get off.....
the modern fillers seem to work well over bare and well sanded / roughed up areas both...it's a myth that you need bare metal.....you can buy metal to metal, filler with glass strands, and lighter easy to mix for those skim coats prior to finish prime..and you can get spot putty for those darn pin holes that always seem to appear when you think that your done....
I'm no body man by any means, but you can spend a ton of money in fillers....Dynalite by Bondo seems to work fine for most applications and is cheaper..it's all in the way you mix it and lay it down....completely mixed and in thin layers...don't gob it on...remember that for a golf ball size of filler you need about a pea size dab of hardner....at least that has always worked for me.....I've seen people try to fill an area that needed more metal work and ended up with 1/2 inch or more of filler trying to fill the void..not going to stay together..also, can't cover rust...it will pop....anyway...to sum it up....unless this is a show piece I'd stick with the cheaper dynalite or whatever brand you find that about 25 bucks a gallon....you'll pay a ton more for some of the other stuff that you probably don't need.... JMHO hope it helps
