I just saw this comparison between the 11R and the PodHD.

https://www.youtube.com/watch?v=Zo9bZNKvdR8

I mostly preferred the sound of the 11R. There were times where the PodHD was laughably bad, particularly the FX.

I remember trying to get a decent tremolo sound out of a Pod HD500 and was unable. It just sounded wrong. Having heard these other examples, it sounds the Line 6 people just settled for mediocre with some of the effects-- even when there were obvious problems to fix.