What is the fit and performance differences between the Triolet and the Summit?

Ah wonderful. I love comparing products. Okay J, let's start with the Triolet. It's a nice boot for summer mountaineering. The sole is rather flexible for a full shank boot, but still provides ample support for scrambling over rocky terrain and climbing up to 5.8/9. The boot is not insulated, so you'll want something warmer if ice climbing is more your thing. The Triolet is fairly light and has what I would call a soild "medium" fit. It's not really narrow, nor is it wide. Now the Summit. I have these boots and thus far they have been great. If you can get the fit dialed, they'll perform just about anywhere. Compared to the Triolet, the Summit fits much wider. I had some troubles with heel lift since the Summit has a higher volumn last than the Triolet. These suckers are super warm, but not sweat-inducingly so. They are stiffer than the Triolets, so front-pointing on vertical ice is fairly comfortable. Indeed, they are heavier, but a much better "all round" mountaineering boot. These boots are both waterproof (Gore-Tex lining) and crampon compatible. The Summit will take Grivel GSB style crampons and has two welts (toe and heel). The Triolet only has the heel welt. I would reccommend the Triolet for summer mountaineering and glacier travel. It's light and sturdy enough for most terrain you'll encounter without needing ice tools. For vertical ice or cold excursions I would suggest the Summits for sure. However it all comes down to how well they fit your feet. If possible, try both of these boots on before purchasing them. Hope that helps