I'm a tech that works on both Rolands and a lot of Epsons. Both the SG3/VG3 and the S-series printers tend to be workhorses. Roland warranty is significantly better then Epsons, especially if you have a Reputable Roland dealer near you. Epson's warranty is only for a year, and not as many people work on the Epsons, Epsons service is hit or miss. The S series can have a few different types of head issues, but usually the machine is at least a few years old before those crop up. The VG3s I've honestly yet to see any real issues with.
As for the pros and cons, I always tell people that if you're looking for high volume, the S60 is definitely the way to go, you won't get a faster workflow then that. But if you don't need that kind of speed, the SG/VG3s are super user friendly, and the ability to print and cut is a nice advantage.
The S40 tends to not be worth it unless you need a more budget friendly option, and the S80 I'd only recommend if the extended gamut is really important to you.