Welcome to the Grumble!
I think we will all be glad to tell you that the one we are invested in is the best, but this is something that really needs some hands-on research - in my opinion. The truth is that most of us are only familiar with the one we bought, so we can't give a neutral/fair opinion of how the others currently compare. For example, we use LifeSaver in our shop - but I couldn't tell you much about Specialtysoft or FrameReady.
Specialtysoft should also be listed in the top products, IMO, as this is another of the popular products. (the above list mentioned only 3 )
We have done annual POS surveys of forum members for the past 9 years, which show what people on this forum have chosen, how many workstations we have on average, how/how often we do backups, how many still do it on paper or use a spreadsheet, etc You can view nine years of results at
http://www.custompictureframing.com/poll_results.htm#tech
My advice is to pick a few products, download their free demos, try the products out with your staff, and call each of the companies with with a pre-sales technical question. This will let you make an informed decision, while testing to see how good the support staff behind the product is.
We're fortunate in this industry to have so many choices in software, and that they're so competitively/reasonably priced. In other industries similar to this one, you would expect to pay upwards of 15k for a POS system, and about $1000 per year for support and updates. The initial investment is almost nothing, and the payback is probably less than year. You'll have reliable price updates available, with daily changes, and won't be leaving money on the table or selling products that were recently discontinued. Your staff will be using a common format that is easy to learn, and produces professional and legible paperwork which doesn't list "part numbers" of the components; which could be taken to a big box or competitor.
The system will notify you when something is discontinued, so you can take down the samples. You'll have a complete customer order history, going forward, when a customer wants to do a piece similar to one in the past - but with todays prices, you'll be automatically building a mailing list as you go, pricing will be much quicker and accurate than on paper - especially when comparing several components. There are many other benefits, but it is the right thing to do. Most systems allow you to have multiple workstations, sharing the same databases. Most will also allow misc sales of art, gifts, and other items. Most will optionally do credit card processing through your internet connection, and can tie into an optional automatic cash drawer, barcode reader, narrow receipt printer, etc.
Good luck on your quest for the best product that works for your situation.
if you run into any general questions, don't be shy to ask on this forum
Mike