Yeah, I'd say multilingual support is gonna be the tough one (what languages are you looking for?).
The two you mentioned both have redundancy-I know Positouch and there's at least one other one that I heard has decent redundancy, but I don't remember the name. Those products mentioned are reasonably stable, too.
I dont think you're going to find too many dealers or those working for dealers willing to discuss dealer prices on here (that can vary with volume discounts anyway). As far as the end user price goes, I will help you there. I would say as a rough figure, for a 4 terminal system, expect to sell it for $3500-$4200 for the software alone (again, thats for something comparable to what you've mentioned-there are some cheaper options).
I would identify the market you want to serve if price is an issue for you. There are software packages that specialize in certain market segments that are significantly cheaper if than ones that do it all.
The best method, IMO, is to contact places that you find through online searches and see if there is an opening in your area. Once you've found out what's available, talk to an end users using that software, and DEFINITELY get a hold of some of the dealers outside of your area and get their opinion of the developer. Ask them how they think the product compares in the market place, how responsive the development team is about testing and patches, stability, ease of use, and how well they keep pace with competitors features.
If you can successfully establish that you're not a competitor or that you don't represent a competitive threat, you might be surprised to find out how willing they are to talk about their experience, especially if they are unhappy. This is probably the most important information you can get, since this is the stuff that's completely out of your control.
