I only own the Neutron but I read the Synchro outsole is better for downhill traction. They look very similar.
The only difference I can see is the Synchro has a cordura nylon upper and the Neutron has a nylon mesh upper. The Synchro says it has a rubber outsole and the Neutron says it has a vibram rubber outsole. The Neutron info on the web site doesn't say it has a removeable insole but I have a pair of Neutrons and the insole comes out. The weight is the same for both of them. If you are interested in reducing weight look at the Horizon boots. They are 8 ounces lighter per pair and the only difference I can see is the heel is 1 1/4" high vs. 1 1/2" high on the Neutron and Synchro. If you are hiking each ounce on your feet is equivalent to 6 ounces in your pack. So that half pound off your feet is the same as taking 3 pounds off your back.
The Difference is style. No matter witch one you choose? You'll still come out
In style. The more color under the sole' and more style' the more we may pay.I own several pairs.
P.S. There the Best Bang for the Buck. You can't go wrong. Good luck. Cheers.
Very similar, and fit is nearly identical. The Neutron may be just a tiny bit narrower. I order an 8.5 wide. Lacing system is a little different. The Synchro has a third hook, which locks the lace in place farther down the boot, a feature I use a lot. The out sole on the Neutron is different, and may be new. I like it. I've used them on wet, mud covered ice, and they hold as well or better than anything I've used before, and that is probably a hundred of pairs of boots. All the Asolo boots I've used seem to last at least a year of hard use. The soles have worn down in about that time, though the uppers are like new. This is fine with me because I then use them when working on shingled roofs. The smoother sole does almost no damage to warm shingles. They also work pretty well for technical approaches to rock climbs. I've never had an eye or hook pull on any Asolo product. During the week I alternate between the different pairs. Neither required any break-in time. Both are really comfortable on my feet, and I've never experienced "hot spots" that I do on some boots. I've used both for kicking steps in spring and summer snow, and with gaiters, my feet have stayed dry. I use good socks with them when hiking, back packing, and easy climbing. They've never let me down when used the way they were intended... and much more. I've been using this type of Asolo boots for about ten years now, in a number of renditions. I've bought them all from Sierra Trading Post, the first pair in store, the others by mail. All have fit well.