What are peoples thoughts on this new update to IPB? Apart from the security fixes what are the pros and cons to the upgrade? Or is it not that much different?

Not too much of a difference. It's a lot more like vBulletin, so if you like vB, you may want to upgrade.

I'm using IPB 2.1 on a pretty big forum, and it's great. I think it's easier to use than vB, but not quite as powerful. 2.1 also has a lot of fancy AJAX and some cool little features in it too.

IPB is a great product. I am a Perpetual licence holder and find it to be more User Friendly than vB in some ways

haha ok, just to let you know I'm a strong supporter of IPB and have used it for a while now so if we could keep it on whether the update is useful or not ... thanks!