Should I buy a fisheye or do pano stitching?

I'm fully kitted out for the gigs I pick up working events and youth sports but I've been getting into urban landscape photography.
Shooting huge expanses of infrastructure is really relaxing but I can't decide if I should rely on pano stitching or a cheap old fisheye for extra large shots. I'd like to hear from anyone who's experienced with either large panoramas of dynamic scenes or fish eye glass.

Gear in question: currently shooting these with the wide end of the gorgeous Sigma 18-35 A 1.8, looking at Rokinon 8mm