The 705 is much better than most, largely because of it's all digital platform and it's tracking system that resets itself faster and more accurately than others.
I'm not going to blow smoke up your butt by saying that you can hunt successfully anywhere, but you will be able to succeed places where many machines fail for sure.
One thing that will stop you though, and that's severe EMI that will put the brakes on hunting with anything but a magnet. The Auto Noise Cancel feature works, but even it has it's limitations. I have my 705 and an Explorer SE, and between them I hunt just about anywhere I want.
A lot of my success is in places that have been hunted hard for decades. Some of it can be attributed to the usual things like nobody ever happened to swing their coil over it before, but then there are places that you know everyone has swung over it and just didn't see it. THAT'S one big reason I'll never sell my Xterra. It has so many user configurable features to explore that if what you're doing isn't working, you just have to try something else....and you can.