But then Vedder can excel when covering "Love, Reign O'er Me."
So he put's in full effort with a clone and half asses his own recipes.
I think that some genres of music are especially suited for unrehearsed, or very "raw" sound. As a comparison I'll refer to an SNL episode the family watched the other day. It had Tracy Morgan, back from the dead, and the music guest was Demi Lovato.
Now I'm not a Demi Lovato fan. Her music is too "pop" and she's too much a kind of diva I think. Her second performance was a crazy raw song and I won't say it sounded like it was recorded in a studio with effects and post-processing. It was kind of out there, but she put a lot of emotion and energy into it, even if she didn't hit all the notes precisely like you'd expect from her. My wife thought she was a terrible singer. I know how hard it really can be to hit all the notes when you are really pushing the boundaries and I thought it was a fabulous effort and really made me appreciate her as a singer and performer to make that risk and put everything she had into it.
It's the same with some of the "grunge" sound bands. They often eschew a polished, produced sound for a raw one. Not everyone can do it, either because they are afraid of making "mistakes", or because they simply don't have the sound for it.
PJ is one of those bands that I like mostly because they can sound raw and sound good doing it. You can really feel what they are trying to get across in the music, and it's still "musical". There are a lot of grunge bands that have a raw, natural sound, but don't have good song structure, or they're not interesting sounding, sometimes to the point of simply sounding formulaic.
Of course, this is all my personal opinion.