We've all made fun of it - chief among us myself - but once in place, it verges on comfortable.
Entry and exit IS tough, but once I'm actually IN and buckled, it's good. The racing seat is set back by the rear bulkhead, which added better than 4 inches of leg room over stock. The seat bolts to the crossbar on the floor, and at it's lowest point it's about an inch from the floorboard - stock is about 4 inches. I've maximized every inch I could, and for a driving position, it works well. The controls fall right to hand, visibility is good, and while I wouldn't want to drive it in a 50 mile road race, I'm sure I could.
About 8 years ago, I was at the June Sprints at Road America, and chatting with a guy out of Colorado racing a Huffaker prepared Spridget. He was about my height, and I asked him how he was able to fit in it. He invited me to jump in and check it out. Now granted, SCCA lets you go with no top, no windshield, and the cage is not nearly as complex as what the SCTA requires, but it clearly was doable.