well the difference might be in the application. v5I is more expensive and targeting people that do real work with their 3d applications and they are used to being able to use their software on both the lap and desktop as where v5e and v5epro target group is home/ocasional users, but well know soon enough. And not to forget here, even if e.on do allow you to have v5I installed on your desk and laptop that doesnt mean that your "friend/girlfriend/relative" can have it installed on one computer and you on the other one.