>Has anyone used (or can comment) on either/both of these two controls for use within VFP? Can anyone recommend another good "collapsable grid" or "multi-column editable treeview" for VFP?<

We need such type of control too.

Now testing:
FlyTreeX Pro
http://www.imcasys.com/cgi-bin/components.cgi?act=1&cid=85

The problem is that there are many controls, pretending that they are the BEST solution. Cannot recommend you anything - should test all of them, whether they are proper enough to your case.