I'll chime in on this. I had a 92 full size blazer with the classic GM peeling paint from those years. I stripped it down to bare metal (alot of work) and then did the $50 roll-on rustoleum paint job over one weekend. If you are talking about the videos on the roll-on method...it actually does cover very well if you thin the paint enough. I wet-sanded in between each coat and did a black gloss color. I put on 7 coats total (alot of work). When I was done I did some final wet-sanding to get rid of any unevenness and then used a DA buffer with compound to really pull a nice shine out of it. I drove it for 2 years like that and it looked great compared to before. It is not a miracle paint like some of these websites make it out to be. I had a cheap car that I did not want to invest much into, so it worked perfect for that. It had a nice shine, and you could see your reflection in it. It looked far from perfect though, and I found it would dull very quickly (ie had to buff and polish every couple of months).

For a Benz, I wouldn't recommend going this route. For a beater pickup, I think it's a great option. Like some of these others have said, a Maaco paint job with some good preparation will look better than a rustoleum job. If you have a body shop friend that does work on the side that would be an even better option (what I am getting ready to do with the 87 300d).

Anyhow, hope that helps.

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97 S500 (90,000 miles) - wife's car
87 300D (298,000 miles and a replacement #14 head)
94 Suburban K2500 - need something to haul firewood
83 300SD (343,000 miles) (sold)