Probably depends on which sites you visit. I had iPad 1 3G since launch day and have never changed my use patterns. Before iOS 5 and 5.0.1, I rarely had crashes. Once I'd upgraded both my iPad 1 and 2, they both crashed on Safari multiple times a day, with much more frequency on iPad 1 vs. iPad 2. The diagnostics logs of both indicated RAM handling probs -- on the same news sites, for instance, I'd been visiting since Day 1 of iPad 1 3G. Since I've upgraded both iPads to iOS 5.1, performance has returned to like-new -- very infrequent crashes on Safari.
I juggle about a dozen iDevices (mine, my husband's and ones I've gifted) on one iTunes account and didn't have any trouble upgrading any of those firmware upgrades. The only difference was in frequency of crashes.
The thing with tech is, not to assume that others' experiences must reflect yours, because we all have slightly varied use patterns.