When revolvers go down, they go down hard. But, contrary to what a lot of the autochucker guys think, this is usually a result of parts breakage. Revolvers are no more or less prone to actual breakage than automatics.
As for "jams", there really aren't a lot of ways for a revolver to jam. If you have an overpressure round, you might have to pound the ejector rod. If you don't eject properly (muzzle up), you might get brass going under the ejector star, and this can be a minor pain to right (really bad at a critical time). But then, you wouldn't hold an auto upside down and try to eject the magazine, either.
If you get some crud under the extractor star, you can possibly prevent the cylidner from closing, but this is fairly easy to avoid (and can be fixed with some water, usually).
By their nature, though, revolvers can't have failures to feed. Failures to extract/eject are easily avoidable as well, since these operations are done manually.
On the other hand, an automatic won't go out of time. But it takes a lot of beating for a well-made modern revolver to get to this point.