We've had three or four really good threads on this in the last couple of weeks. So even though I vowed never to say this, you should probably do a search.
That said, I can't say enough good things about the 710, so I will answer your questions anyway.
What does everyone think about these?
Many people agree with me that it's the best production 4" folder available.
I've heard a few people say that Benchmade puts too wide an edge on them. If so, is it hard to reprofile with the sharpmaker?
They used to do this, but they seem to remember how to sharpen knives again. Mine came with a wide edge. It's easy to reprofile with a Sharpmaker
if you have a couple of extra little things laying around.
What does everyone think about that axis lock?
It rules the planet. See the poll going on right now.
How would the 710 compare to say the Chinook or Starmate?
The Chinook is a behemoth that I like a lot. But it's very different. Different blade shape, length, lock (very good lockback, btw), etc. It weighs about 45 pounds. Not nearly as smooth or fun to open as the 710.
The Starmate is a little closer in terms of purpose, but has no recurve, has a linerlock (the opposite of an Axis lock in terms of reliability, methinks), and has only one liner. I love Spyderco but it'd be hard to claim that the Starmate is "better" unless you insist on an opening hole and CPM-440V.
If I did get the 710, I would use it for virtually everything. Any thoughts?
You and half the other knife fans out there.