I've used a foxpro for quite a few years now and can say, hand on heart, that it's definitely worked on many occasions - seem to have the most success with the actual fox calls ie yell, response and distress/fight - it's uncanny how they can appear after 10 minutes and end up within 5-10 yards of the caller itself - their in-built laser guidance obviously works. I guess they must take a bearing as I've watched them walk out onto the field, get to a point and then change direction straight to it.
It's the 32 calls model but I guess I only use the fox and the other rabbit/hare/mouse distress calls so probably around 6 or 7 variations.
The biggest bonus is the remote control which means they're not coming in right on top of you - although I do put the call 'out to one side' so you're not actually in the line of sight of their approach having been bumped a couple of times. Best result was five in one evening, all within 5 yards of each other and I guess the whiff of blood also helped.
Have also used the fox yell to get a dog fox to sit long enough in the lamp for a long, long shot (301metres). Fox fight also winds up the Fallow, and the crows which in turn attracts any nosey fox that happens to be close.
Don't use it all the time,, if I feel it's not right, so as not to overdo it on the education side.
That's me 5p's worth,
ATB
FBW