Its a good coil, just slow down in compaison to the 'smaller' coils as it scans more ground and could need more time.
My budd has a XT-70 but rarely uses the coil.. I think he's afraid of the size..
I don't use mine anymore because of the weight. I use my 6" all the time and the last time I used my 10.5" it felt like a 20lbs weight in the end of the shaft. it is a good coil though found lot of stuff with it