I originally just wanted this game for the exporting. But after playing some of the actual game, not only was I pleasantly surprised, but I've found that some aspects of it make the game seem superior to RB2. Now don't get me wrong, I'm not calling LRB a better game. In fact, there are ways in which RB2 is better. But I'll get to those later.
1. The customizable rock den.
2. Being able to change your character's face without having to delete and recreate him/her.
3. Money shared among the whole band is convienient. I found it a bit of a hassle, having to keep switching among my characters in RB2, just so I could make them each afford the instruments and clothing I wanted them to have.
4. I love the rock challenges that you come across in story mode. They're quite fun to play and entertaining to watch. It's also cool to see your bandmates doing things in cutscenes and not just posing in loading screens.
5. Recovery mode. Not that I would've needed it much in RB2, unless I were playing on hard or expert. I never was able to get through that blasted guitar solo in Flirtin' With Disaster on hard.
Now for the ways in which RB2 wins.
1. Online play. Not exactly something I can't live without, but it is nice to be able to play with friends, without needing to have them come over.
2. Nobody ever sings along with the lead singer in LRB. Most people might not think much of that, but I really liked that aspect of RB. It made the band members look like real team players, and in some cases looked pretty cool and was quite fitting. For example, in Spoonman when my singer sings "All my friends are in the air," and my bassist is the one who follows up with "All my friends are brown and red."
3. Aside from not being able to change your character's face or choose different people to serve as your road crew or entourage, the rock shop is better in RB2. You don't even know what's for sale in the Lego rock shop until after you've unlocked it. You might buy one instrument there and then suddenly unlock one that you like better and think, "Aw, man! I could've saved for that one!"
4. The band roster works better in RB2. Maybe there's a method to it that I'm not aware of, but I'm not finding any way to assign my characters to specific instruments in LRB when I'm not playing as them. In RB2, I can easily have my other three characters fill in the other roles while playing with my guitarist. And if I decide to play an all female vocal setlist, I can switch her with the singer and play the guitar as him.
Final thoughts: I can't really say that either one is a better game, but I still like to play RB2 just for fun and the LRB songs are a plus. And despite its flaws, LRB is still a fun and cleverly-made game. I'll definitely want to at least finish its story mode.