I personally wouldn't recommend buying them this year, due to the lack of ability to buy lenses(In the uk especially). However next year there's most likely going to be a lot more distributors. The goggles themselves aren't a huge improvement over I/O's, if at all, which Is why I'm going to be sticking to them, as they're cheaper and the lens changing is a breeze, whereas the I/OX's are just a hassle.
They worked great, no fogging, huge peripheral vision, easily adjustable and easily usable strap.
However they are incredibly poor in the lens changing department, slower than I/os' and much slower than I/O's, mainly due to the fact that you have to twist the outriggers around to release them, I feel there's too many contact points.
Coming in a wide variety of designs and colours there's a choice for everyone.
The product itself has an excessive rrp, and the cost of additional lenses are ludicrous, although this is the first year they've been sold.
The fit seemed significantly improved, especially with regards to how they fit with a helmet, fit perfectly with my very old head rebel, which Is my first set of goggles that have.
I can't comment on the durability, as I wasn't putting any excessive force or pressure on them, but I find they scratch a lot easier than I/O's, not sure if that's just a coincidence, but that's what I found.
I personally have always been a fan of Smith goggles, and after 2 years with their I/O models I really didn't think there was much to be improved on. They managed to prove me wrong though with the I/O X here. While there is only so much to be said for goggles, these do everything very well. They expanded field of vision gives a huge amount of peripheral view, and you only see a small section of the frame at the nose piece. Everyone I've given these to to try are hugely impressed with just how much you can see. The lens swap has gotten a little more difficult since the I/O, but once you have the hang of it, change outs are a breeze, a huge plus on variable days. I used the Blackout lens as well as a lighter Ignitor lens for overcast and even nights. There really isnt much more than those 2 I feel I need. One thing I do hope they change is the goggle case with the extra lens storage area they sell, while it worked great for the I/O, the new I/O X lenses are just a little too big and arent fully protected in the case.
The frame shape does a great job sealing with a variety of different helmets I've tried them with, though obviously the best seal is with the Smith helmets.
All in all, I remain a huge fan of Smith and their goggles.