Yes, louder pops occur sometimes when changing sample rate, which isn't too bothersome when you're listening to an entire album at the same sample rate (but might be on a random play list). I think it should be avoidable by a high end DAC (my Benchmark DAC2 makes no noise when switching sample rate).
But also, I've been using native Mango, which has the problem of not playing album tracks in order many times. So I though I'd try the Android Mango player, to see if it played them in order. I've only listened to Android Mango for a very short time, just testing the track order. And it did seem to play the track order back for the album I was listening to in the correct order. But it was a 24 bit, 96k album, and I noticed little ticking noises in the audio at the beginning of a track or two, that weren't part of the source audio. It seemed to clear up as the track progressed. I just assumed it was a known bug that would be fixed, as I hadn't noticed it occurring with the native Mango. I'll have to listen to the Android Mango more, now, to know for sure what that noise was, and when exactly it happens.