Wayno

I use Tracker system, it's good. Use it on my Beagles in the Mountains chasing Sambar Deer, and also on my Pig Dogs. Once you get the hang of it it's real easy, the size is the best thing. Don't know anything about the contact pro system sorry.

I have a 40ltr Waeco. I like it a lot it does the trick for me. Cheaper than the others but still runs the same Danfoss compressor.

I have a Maxima Tracker 2000/25. I run it on my Beagles hunting Sambar Deer in some real harsh VIC mountain country. It also see's use on my Pig dogs up north. I agree that if you don't know how to use it properly, it can send you backwards. Now that I have used it a bit, I have no trouble finding my dogs. I think it is great, fits in my backpack easily. I need a unit I can run around in the thick scrubby mountains with and I sure couldn't do it with the big aerial types.