1st gen SC is not worth the extra cost. You must run premium. The SC is known to have to be rebuilt and the Knock Sensor WILL go bad causing the ECM to cut power from the SC. If you are looking for SC get the codes pulled before purchase (this goes for non SC).
1st gen is underpowered and a bit slow and sucks gas. But it's got lots of torque so if you need it to haul you will not have an issue. Also, there are not a lot of after market parts.
Other 1st gen problem areas is the KS, 2000-2002 cracked exhaust manifold, gas tank rust, and that is about it for the major stuff.
The 1st gen is a pretty tough little truck. But double check then you buy it that the timing belt was changed at 100,000 miles because they have belts and not chains in the v6.