If Ω's ridiculously paralytic review of the Sony A7r wasn't your thing, how about checking out About Photography's review by Tom Grill? It is concise and backed with performance comparisons with the Leica 240M.
Tom believes the A7r isn't ready to replace your digital Leica system. He concludes that we must wait until Sony have brought to market comparable Zeiss lenses. Then and only then will the A7r show its mettle.
You can find it here.