Here's an interesting comparison between RoR and Django:
vaporbase :: Postings
Its quite a long analysis.. but from the final conclusion, RoR beat Django overall. But, the latter won (barely) the "technical" side of things. One has to read through all the 15 parts to get the whole picture. I'm not going to bother just yet though
Keep in mind that this analysis was made a year ago. Who knows how much things have changed to both of them.
Am downloading Pyro now btw! *rubs hands in anticipation*