I have been riding GS500E for about eight months now, and it has been a brilliant experience overall.
Easier availability of parts
Low maintenance cost (If the bike is restored perfectly)
Good fuel average
Good for long rides
Air cooled engine is brilliant
Bike in market since 1989 with no major changes which speaks for its engine reliability
Less throttle response (compared to 4 cylinder bikes)
Should have got dual disks at front (My 250FZR had far better brakes)
In Pakistan, to buy a GS500E it is important to make sure that it has been restored with good parts from a good mechanic. Otherwise, the bike will give you numerous issues from time to time. With perfect parts in the engine the bike is a joy for a long time.