The unfortunate thing about this movie is that in order for it to be fully appreciated, I think a second viewing is essential. It wasn't until I watched it the second time with the knowledge that Bale was really playing two characters that all the subtle genius started to show.
For example, his reaction to hearing his wife was pregnant seemed awkward the first time. But when I realized that it was his brother's wife and baby, not really his, what was a simple scene on the first viewing became completely loaded and I was in awe of how Bale pulled it off.
I say it's unfortunate because that's the reason the movie doesn't get the recognition that it deserves. So much about this movie was Oscar-worthy, including Bale's performance. On the other hand, Jackman was great and he was perfect for the part, but his character wasn't as challenging I don't think.