As of right now, the only channels that are digital in the immediate Spartanburg area are USC-Upstate, GSP Airport Operations, and SRMC Emergency Preparedness folks. All Fire, EMS, and LE channels are analog at this time. It's unknown when that might chance, but I don't expect it to happen any time real soon.
However, several surrounding counties are mostly digital - Greenville and Laurens, most notably. If you expect to take your scanner on the road in SC, you'll definitely want a digital-capapble scanner. And as upgrades are made to the Palmetto 800 system over the next few years, most agencies using that system will be digital.
So, if you're looking to save money now you can get by just listening to most Spartanburg agencies with a non-digital scanner. If you want your investment in a radio to last more than a couple of years, go ahead and invest in a digital scanner.
Another thing to consider is programming software - do yourself a favor and invest in a computer-programmable scanner, cable and software. I believe a cable is included with most Uniden-made radios, but you have to purchase them separately for RS/GRE scanners. You'll have to purchase new software when you change radios, so factor that into your budget.
One other plug for RS/GRE scanners, I live in Spartanburg and have a pretty good collection of programming files for the Spartanburg area for these scanners that I'm happy to share. Contact me via email or PM for more information.
If you're going to spring for a digital scanner, I like the hand-held PRO-106/PSR-500 model (same radio, same manufacturer, slightly different appearance). There are mobile/base versions of each (same radio/operation, different form factor) depending on your preference.
For a non-digital scanner, I'd choose the handheld PRO-164/PRS-400, with mobile/base versions available for each.
I don't have any "current" Unidens in my collection so I really can't comment either way about them. Some folks seem to like the Unidens for their smaller size, included accessories, and different memory structure. There are no local retailers for these radios that you can get "hands on" experience with.
The Radioreference Wiki (use the Wiki link at the top of the page) has articles with specs and pictures for all these radios. The Radioshack scanner forum has threads that deal with PRO each model as well.
The PRO models are available at RadioShack. Use the store at Westgate Mall.