If you really want to, you can go through the release notes to find out what has changed from H22 to H26, but there shouldn't be any issues or things to consider from the upgrade. Mostly it has been some refactoring of the core code to make it more efficient, though there have been some additions and changes that enable you to take advantage of newer reporting capabilities and some other stuff for tracking (which is kind of irrelevant if you aren't planning on changing your implementation).
Sidnote: I kind of wonder why you're second guessing your Adobe Consultant, in the first place though.. is it an Adobe ClientCare rep, or is it some 3rd party consultant? If it's the latter, perhaps this is an indication to find a new consultant!