On a recent trip to the US from the UK my wife and I each used a BlackBerry Playbook with the built-in video chat. It was perfect -- no discernible lag and I was able to talk with the kids with great video and sound quality.

So, perhaps Skype and GV are suffering from over-extended networks? It must be hard to justify investing in better network infrastructure for a free product (or when your revenues are minimal). On that note, I don't get the impression that BlackBerry's network has much of a problem with network load these days...