The Scarpa Zodiac Plus GTX boots are the beautiful offspring of a lightweight hiking boot and a mountaineering boot. They can handle any degree of technical hiking and scrambling in the summer, and they can take strap-on crampons for shoulder season and some winter hiking. Durable and very waterproof, these boots are fantastic, but they run very hot, and have a very stiff sole that takes even a few months to fully break in.
I was in search of a hiking boot that was serious enough to use in the winter (with crampons) but also light and comfortable enough to use on summer hikes. I settled on the SCARPA Zodiac Plus GTX boots, which Scarpa advertises as for when a hiking boot or approach shoe is too little but a mountaineering boot is too much - and that's exactly what they are. They are well-built and very solid boots, with a stiff, grippy sole that is surprisingly good for both small footholds and smearing against rock.
The Zodiac boots are very waterproof - in snow, rain, puddles, and mud I have had no water leaking in. However, as with many waterproof boots, they run pretty hot - and several times I've found my feet sweating from the inside. I think this makes the boots a good choice for cooler weather, and particularly for shoulder season, winter, or for alpine pursuits rather than hot weather hiking.
The lacing system on the Zodiac boots is great in my opinion. It's quick while also being easy to get a good, tight fit. The ankles are padded suitably, providing great ankle protection and support without being restrictive or uncomfortable.
Despite my best efforts, the Zodiac boots have held up surprisingly well. The suede leather uppers are somehow extremely durable, and have held up to plenty of scraping against rock, not to mention the enormous amounts of mud they've also withstood. The soles show little signs of wear after months of hiking on rough talus, and are still as grippy as when I took them out of the box.
However, the stiff sole comes with a drawback. My main complaint with these boots is the break-in period. Because the soles are so stiff, even after months of regular use they remained very stiff. It took around 2 months of breaking them in before my feet felt comfortable after a long day. Even still, because they are so stiff, I will favor a more comfortable trail runner for any non-technical hikes, and reserve the Zodiac boots for anything that requires more serious scrambling or maybe a really heavy pack.
If you're a summer hiker or a backpacker, this is probably (definitely) more boot than you need. If you need something just a bit more serious, be it for lighter alpine adventures, for colder weather, or for winter hikes where you need strap-on crampons but not a full mountaineering boot, then you'll find the Scarpa Zodiac Plus GTX boots to fit the bill perfectly.