I like Gerrit diff system. Yeah I know that sounds like trolling read below though before discarding this mail.
Sure, inline comments are cool but I think they lack discoverability. You need to browse all the diffs just in case there's a lonely inline comment there.
Suppose hashar commits c1234. Ahar Voultoiz reviews a couple of files and adds an inline comment 'This feature is PHP 5.4 only' Then Antoine Musso does git review -d 1234, finds it fine and approves it.
I think inline comments should also produce entries at the comments section.