I use the magnetospeed V3, so far I love it! The data logging mailed it easy when switching between different loads.
I've got a magnetospeed and a labradar. Certain situations the labradar is great, but if your range has a low baffle, there's a good chance it won't work. The magnetospeed is the one I recommend most often and it's a great piece of equipment.
The magnetospeed will be my next purchase.