Dave I just picked up a used 10x12 SEF butterfly coil this winter and have only been able to use it a little as here in Northern Wisconsin its still very much winter. The experiences I have had with it seem to be pretty good, depth seems good, I am still having a small issue with pinpointing with it, but I think I will get that skill honed in a bit better as I get a little time behind it. I been running the pro coil on my explorer previously with great results. I guess my only gripe on an SEF coil is the wieght of it, it wieghs a ton next to the minelab procoil. I hope others will chime in here on this as I would like to hear other opinions of it myself
HH
Slipperyjack47