[AKG240]

So I've been using my trusted AKG K240S for over 7 years, this is basically the only good (relatively speaking) pair of headphones I've tried. (when all your friends use 30$ headphones, you feel that your 80$ pair is pro level and there's no need for anything better).
Lately they started falling apart, both esthetically and technically, so now I'm looking to upgrade.
 
I recently purchased the Klipsch iS4 to be used with my iPhone. Great little in-ears. However, as great as these are, I want a full-sized "open" pair to be used with my macbook.
 
I'm pretty much set on the HD 598. I can't test these (or any other higher-end pair for that matter) where I live so I based my choice on reviews.
I love a big sound stage, tight but not overpowering bass and detailed representation of the recording.
 
My question is, is it really that noticeable of difference coming from the AKG's? I'm talking specifically about the HD598. I want to ask whether I'll be blown away, but that's obviously something only I will be able answer after testing them.
I'm still interested to hear your personal impressions after upgrading from X to this pair.
 
Thanks for reading.

 
Leo