I'm not sure why people think diesels are slow. Modern diesels are torquey, fast, clean and don't smoke unless you mess with them. Diesels have won LeMan's, Baja, and other races. In everyday use I get to see my brother's vehicles. That guy owns far too many cars for his own good, among them several Jetta TDI's, Passat TDI's, older and a newer Dodge 2500 diesels, a Ford diesel, and a diesel Suburban. He tweaks them, but the diesels are faster than their gasoline counterparts and the VW's, paradoxically, got better mileage after installing bigger injectors. His 95 Jetta TDI regularly sees 58-65mpg on highway trips depending on how he drives. I thought he might be selling me a tall tale until I had to ride with him on a 750 mile round trip last year and we didn't have to stop for fuel once. Then again, I shouldn't have been too surprised. I used to see low 22mpg hwy in my 9000lb, 4X4, extended cab, long bed, souped-up (~500hp/750tq) Dodge Cummins riding on enormous tires for pulling 5th wheel trailers through swampy fields.
There are diesels at drag strips also.
I'm obviously a diesel fan and I'm biased. However, I can't really think of anything that gas engines do better compared to a properly tuned modern diesel. In comparison to gasoline engines, modern diesels are more reliable, FAR cleaner burning, get better mpg, and have similar drive characteristics. Win win
Just my $0.02