Mine run great. I have replaced the valve springs, head gaskets and did a valve job on them. Yours will need the same as they have at least six seasons on them.
I think carb motors are easier to upgrade and as reliable as EFIs. The "old" technology is easier for the average guy to learn, maintain and fix when needed. Its not rocket science. You can be taught to change jets, but not map a fuel curve.
Good luck either way you go.