In reply to steveej:
Hi Steve,
We feel that they're very similar boots in terms of where you'd use them. The main differences are in fit - The TNF Verto S6K is slightly narrower at the front yet broader in the heel than the Scapa Phantom 6000. Anecdotal evidence suggests that the Scarpa is a touch warmer, although this may be down to the extra space in the front of the boot.
Other differences - the Verto inner boot is more durable (it has some sole on it) and better for slumming it around the tent. You'll also get a more precise fit as the inner is laced (Scarpa just fastens with velcro). The Inner boot is gripped quite firmly by the outer, so you may find you need to put the boot on "as one", whereas with the Phantom you can put the inners on first, then put them into the outer.
We like the way the zip on the gaiter wraps diagonally around the boot - this gives you a wider opening to get your foot into and minimises flexing across the zip itself. This is a design feature that Scarpa will be putting into the next version of the 6000 (but don't hold your breath for them
http://www.outside.co.uk/latest/news/Sneak-Peek-at-the-2016-Scarpa-Phantom )
Ultimately, get the ones that fit the best. But then you knew that already!