I have not seen a 10/11 mirage in the flesh, but they do look great. Looks like they've changed the colors up and raised the pockets so accessible while wearing a pack waist strap.
I have a new 09/10 Mirage. Fit is very similar to Beta (only tried on the Beta) with the Beta being a bit shorter in the torso, which I like.
The rest is Pro Shell vs eVent.
I found this quite informative for the main difs between the two:
http://www.climbers-shop.com/Waterproofs.aspx
I think Gore breaths very well and I am a heavy sweater. The Mirage I have is brand new so I don't know how much better it breaths, but all claims seem to indicate it's a very noticeable difference.
Oh, and Deadmonton...if you're in Edmonton, are a size medium and want a great deal on said Mirage above, PM me. It was an impulse buy and I doubt I'm going to use it.