They were both Excellent
but I'll give the slight edge to "Because You Left."
I don't even really know where to start. It was just completely worth the wait. I thought the pace was fast last year, but I'll wager going back to watch Season 4 will seem practically glacial by comparison.
I'll have to watch them again for more detailed thoughts I guess, but Hurley and Sawyer kick ass is where I'll leave it for now.