I've used ProSeries for many years and always been pleased. It's a quality software program with good technical support and an excellent price tag.
When DMS was introduced, I investigated and even gave it a test run. Like JAD, I couldn't understand why anybody would want to buy or use this product. My practice is 100% paperless. I simply scan and print my work papers and returns, respectively, to PDF documents and save them to a carefully-organized section of my C:\ drive. I backup the client files every night, using 3 rotated generations of physical media.