Tip #1 Before any review takes place for any organisation considering a major software change, ensure you have the latest understanding of what your current systems can do: When I ask why I am being asked to help, more often than not, the firm is not using the software to its full capability; I always suggest to have the top sales person from their incumbent vendor ''re-sell'' the product to them as if they were a prospect.  Why? The top sales people are ALWAYS across the latest ‘bells n whistles’' which they highlight to prospects but which often are not recognised back to existing clients.
The challenge for sales people though, is that they are often remunerated in such a way that they need to move quickly from one prospect to another rather than re-visit existing clients as commissions are only paid when each module is first sold, rather than first and subsequent recurring revenues.   This is why the common complaint of ‘'they only want to see me when they have something to sell’ echoes throughout the market - sales people simply do not make money revisiting you unless they have something new to sell you.   Sales is one of the few jobs that you can keep score at the end of every day.  

Tip #2 : Many firms I meet do not read release notes or even have someone in-house to ‘interpret’ what the updates might mean to the firm.  Not reading release notes is like having the latest version of Excel, but only using the capacity you learned from 1993; completely pointless.  The software has significantly evolved and added many, many new features.  If you are not using it correctly, that is not the fault of the software, it is a fault of the user.  Any software application you purchased was to fix an issue or challenge at a particular point;  using it after the problem has been fixed without understanding what else it can do, results in wasted time and effort on your behalf.

Tip #3 : US companies will bargain ferociously in December, Australian companies in June - end of financial years (if you can afford to time it) are a great time to get a good deal.

If your relationship with your vendor has broken down, then that is entirely another issue: I’ve seen a few of these recently.  Tread carefully and change for the right reasons, but most of all

Be wary of greener grass…

Alan