I never found the coinsearch coil to be outstanding its only attribute was its physical lightness ; its not waterproof , apart from that there,s no performance advantage .Sovereign coils are making good money right now as are the the older machines XS and XS pro .
Ive had both and I still retain a Gt,because the reactivity of these machine is slow compared to the modern single frequency machines of today ,but nothing touches BBS or FBS on the wet salt sand ,,
The most useful coil IMO,, is the eight inch , its reactivity is quicker and it gives you better target separation , to my way of thinking the eight inch is a better buy ...what ever floats yer boat..its only a hobby .....