Picked up the ProSpec X7 electromagnetic field detector (£189.99 from Paranormal Direct) last week, and I've had it out on three investigations now. Thought I'd give my honest thoughts before recommending it to anyone else.
The Good: Lightweight, easy to calibrate, excellent build quality. The dual-frequency readout is genuinely useful - haven't had false readings from nearby electrical cables like I did with my old Trifield meter. Runs for about 12 hours on four AA batteries. Comes with a nice carrying case and the manual is actually readable.
The Not-So-Good: The audio alert can be a bit twitchy in older buildings (tested this at Borley Rectory last weekend - bloody thing was shrieking constantly near the original foundations). Also, at nearly £200, it's not cheap. You might get comparable results from a £120 EMF-390A if you're just starting out.
Overall verdict: solid piece of kit if you're doing serious investigation work. Not essential, but it's a step up from the budget options. Anyone else tested one?