the biggest different on bis 2.4 is auto login..
which is a pain for user who frequently tested new device, must be deactivated first by login to your bis website using desktop or maybe using operamini to revoke auto login feature..
if you using your email setting to login to your bis website, it will show change handheld procedure, beware please make sure you know what are you doing
even there is a funny thing that we are required to answer if we are going to change to the same PIN :p just choose -NO-
this feature is great for a new user
and by the way apac (asia pasific) using this new bis since last week.. at least my carrier is
beware if you take your simcard to other blackberry, make sure on the bis website that you are tied to right pin.. (unless you have revoke the auto login feature , so you must login to change handheld)
and other new feature, is if you create user must accept agreement first before creating user name, and for existing user there a end agreement link on the bis website (haven't tried this)
cmiiw, at least that what i known from the new bis 2.4 ..
i miss my bis 2.3 :D