It was a massive disappointment for me. The 5.1 mix is unbalanced and one of the worst mixes I have ever heard. Normally, they will make the center channel for lead vocals, rear for backing vocals. They abandoned this approach and created a seemingly random channel setup from song to song, in which certain instruments are less audible than the stereo mix. "Dead" is particularly bad. I listened to it a few times, and now it is collecting dust. I wanted it to be like Avalon 5.1 mix - it's not.
I believe the stereo mix is from Mofi's Doolittle SACD. It sounds good, probably the best version of Doolittle out there. I can't say that SACD, or other Hi-Res releases sound significantly better than the CD form. I would only say they are about 10-15% better sounding on average. However, the MoFi release is probably about 25% louder than the original CD, which is good in my opinion.