PDS is the position sensitive damping shock. Basically it is the non-linkage rear suspension.
With proper suspension valving and motor tuning, I think the '98 is a fine bike. The powervalves are adjustable - if you want better mileage and smoother trail manners in the tight stuff, set the powervalve to open later than stock. It will still have plenty of low end, yet will rip on the fire roads when you do crack the PV open.
IMO, the 300 has plenty of motor, even for the desert.