Interesting, I've never tried those. Lightweight is good of course, and vibram soles are good. In my neck of the woods I'd be principally worried about water coming in, it's pretty wet and muddy most of the year here in England (our rain is world-famous!

).
Did I mention I live in the Pacific Northwest?

The
Other Emerald Isle. Included in our nearby biomes is the
Hoh Rainforest with 140" annual inches of rain. We understand wet. You'd also feel right at home on the
West Coast Trail, just across the border into Canada.
With the GoreTex versions of the SG5, the main problem I have with wet feet is the hole in the tops of them where my feet go in. If I'm not wearing long pants (because it's muggy and wet, and I run metabolically warm) or gaiters, then eventually the water runs down my legs and starts soaking my socks from the top down. I'd rather my feet were wet than the rest of me soaked in sweat so I suck it up and carry extra socks. The SpeedGoat mids lace
very snugly to the foot. Unless you didn't lace them up, they aren't coming off. The low tops are much more like a standard trail runner, you could find yourself fishing for one of those in deep muck.
And also the risk of them coming off your foot in the mud. We have a big problem with ticks, there are deer everywhere that carry the ticks.
We have ticks here too, we just keep an eye out for them and pick 'em off and crush the little suckers between my thumbnails before they get a chance to burrow in. My cushioned wool hiking socks are an adequate deterrence. We also treat some of our gear with permethrin.
I'm wondering how stiff those soles are on rocky trails? Traditional vibram used to be super-stiff but I'm wondering if those trainer-style soles are similar. They certianly look pretty thick and spongey!
They aren't stiff, that's kinda the point. Traditionally, if you were hoofing it around with a pack, you wanted a stiff Vibram sole for good traction and to keep the sharp pointy rocks from poking through your burdened soles and hurting your feet. This is a different game, instead of a hard unforgiving sole 100% of the time, just cushion the sharp pointy rocks and have a soft cushy sole all the time. These are far more forgiving and much much nicer on the knees. When trotting down a mountain trail, their ability to conform to the trail surface usually provides better traction than a stiff sole.
I only wear my stiff soled boots for extended alpine or glacier travel on foot, where I might also need crampons and extra warmth. My "heavy" boots don't get a lot of love any more, I'd much rather tackle such climbs on Alpine Touring skis, where the return trip is dramatically faster and more fun. Even my lighter leather boots tend to only see action when I'm doing volunteer trail maintenance as a sawyer and they're mandatory PPE.
Yes, the SG5s are expensive. But so are knee replacements, and quality hiking boots that require little or no break-in period.