i have used a Super Fly for the First Texas Greek Series.......including an Omega 8500 and a Teknetics G2+ along with one for the Garrett AT Pro/AT Gold. The Super Fly outperformed the FTP stock 11"X7" Biaxial that Monte mentioned and the 8.5" X 11" stock Garrett coil.
By outperformed I mean, it was as deep or deeper, had better target separation, more stable target IDs, less susceptible to EMI, and felt as light or lighter, with better overall weight balance (center of the coil mounting) than the other coils and obviously has better overall ground coverage because of its dimensions. It rivals the Detech Ultimate 13" coil performance wise which is saying a lot since that is an outstanding big coil.