The R2J has a higher bitrate by a fair bit (about 25+%) but as you can see the improvement is less than negligible. They're both missing a bit of the bottom or top respectively so they're even in that regard.
The R1 has subs, the dub (it's average) and the OP, ED and bumpers for each episode. The R2J's only have one OP/ED per disc as the episodes are all one title, there are no bumpers and the episodes are just seperated by a preview then a short screen with the episode number. I prefer the R1's...
The R1 thinpack is missing the mini movie and web movie and any other extras but hey, you'd only watch them once. Sadly it also misses the TL notes which are essential. But thanks to the internets I have the notes for discs 1-5 (with plenty of free typos) so I'll try to get hold of the rest and compile them nicely.