I have the Pro-197 (which is the Radio Shack version of the PSR-600) and love it. Great radio. The ARC software though..... not a fan of that. I would recommend taking a look at Win500 or PSREdit. Thankfully they all come with free trials so you can kick the tires yourself and see what works best. For me, I ended up buying PSREdit.
i have the pro 106 which is the radio shack version of the psr500 it is a good scanner had it since jan and never had a problem (knock on wood) i used all the programming software for the scanner and found that win500 is really easy to use with the scanner and i agree with what forts said about the arc in my opinion that that software is not user friendly compared to win500 and psredit