I own a PodXT as well and have owned various tube amps and digital simulators. Don't believe the hype - while digital modelling has come a long way, it has a long long long ways to go to match a good tube amp.
The Pod's simulations are also limited by its software. For instance, you don't like the choice of amps Pod simulates or you really wish Line6 would offer a VHT sim? Too bad.
At the same time, I like my Pod. Actually, I love the little bugger. Not only can you record without having to have deaf neighbors, the Pod does a lot of things that no tube amp will do, or at least without a huge budget for hacking up vintage gear.
For example, want to run a 120W Fender Twin amplifier cranked through a 1x10" Gretsch speaker cabinet? And not blow up a speaker? No problem! You will fidn that some of the best Pod tones come from some outlandish combinations of gear. Then you want to save your amp settings to reproduce your tone later? Done.
The trick is to see the Pod for what it is and work with that, and not ask it to be what it is not.