If you like Rock Band and want a few more achievements, go ahead and rent this. If you buy it, you can add the 20 songs to your main RB library, which is nice. Personally, I had trouble calibrating the game (I had trouble calibrating the Country Track Pack too), even though I had no trouble calibrating RB1, RB2, Lego, Beatles or GD. Maybe it's just me, but that seems like a pattern that points the blame at the Track Packs. Anyway, it made the Flawless Fretwork achievement impossible. Overall, it's just a Track Pack- don't rent this expecting a whole lot.
I play plenty of RB2, and even have about half of these tracks purchased already, but Gameflew it to milk a few achievements out of it.
I spent a couple hours in one evening playing by myself, got 180/250 and put it back in the envelope. Parts of the last song in the career is a bear, even on Hard (I usually play on Expert), so beware.
Thrice I should have been awarded the 100% Expert Bass Upstrum achievement, but it didn't come, otherwise I'd have gotten 200/250.
No reason to own this, but it's fun for a day or so.