I jumped on the bandwagon and got an ipernity account too, but I really don't like the feel of it. I can't work out the navigation, or what anything means, or how to do anything!
I'm staying with Flickr. Not for their benefit, for mine.
e2a: ok, this has just spurred me to go and have another look. And oh my gosh could it be more of a rip off of Flickr? Some things are practically identical!