I own the BH 202 with three different coils and had only one problem with one of the coils, I tightened the coil wire too tight and it sometimes shorts out. I have made many finds with the BH 202 and my wife uses it with the 5 coil.
I did want more and upgraded to the F75 and going through a learning curve right now. I may add a AT Pro or a Soviern GT later on. I would not call the BH machines cheap. They really do a good job if your just getting started.
Once you upgrade, you will have things like EMI, threshold, sensitivity and such to deal with. Good luck and remember you cant find it if you dont walk over it.