If you ask most framers, they will tell that they "love" what they have. Possibly it is because either they haven't used anything else or are so deeply entrenched into their current system that they are "afraid" to do it all over.
A POS system can be THE most powerful tool in your business as it is "responsible" for what you will charge (and if used) can yield significant data that will help you make business decisions based on facts and less on emotion or, "I think".
With that in mind, I could never think about such a long term investment and relationship (because THAT is what you are really buying, not just "some program" but the assistance after installation and the ability to have custom "tweaks" written to make the program more tailored to your busines)s - WITHOUT eye to eye meetings with representatives of the companies, the ability to see the screens, try the programs and perhaps take some "free" courses offered by each of the companies.
A trip to the WCAF could more than pay for itself if you ONLY went software shopping. Some of the most talented and experienced framers in the industry will be there. You will have networking abilities to discuss with end users (and also industry leaders/users who might not post on this forum) of their true experiences.
I will share that I invested a substantial amount of money in one company for a system that never worked (it was intended to link my multiple stores and be able to track real time inventory) and learned my lesson the hard way.
I would also ask those who are the "consultants" in the business what they use/recommend because should you decide to avail yourself of their coaching, having/using a system that they are familiar with might be a significant advantage.
GO TO THE WCAF.