I havent used an MR3 lately, so can't comment on the difference between the two. I have MR2 LA's, tried this TR3 due to it's look and feel, the reel is nice. The thing is, I don't like the large size, just my preference. Probably has something to do with the fact that I prefer and will only use a 9ft rod. This reel just seemed totally out of balance to me with that short rod large reel combo.
I have gone back to the LA's, while they definetly creep a little more, I'll put up with that.