The conversion process is pretty straightforward, at least in my experience.
The gain is you get onto the latest, best supported version of the product.
I do alot of cost-justification for customers when they get fed up of not being able to fix or develop their Legacy systems. After all the meetings and arguments if they go ahead with it they almost always go on to upgrade more stuff once they see the benefits of not having to find a PC with an ISA slot or the old copy of Windows98.