If the GT 2170 had its own Facebook page, it would get more Likes than any other running shoe. This shoe does many things well for many runners.
The 2170 is the shoe a large chunk of runners would wish for if they were stuck on a desert island (no, it's not a great shoe for the sand, but you get our point, right?). The 2170 is impressive not for any one standout feature but instead for how well it integrates a range of technologies to create a cozy shoe that lets the miles go by with ease.
Our testers were universally positive about the 2170's heel-to-toe transition, but a few of us found the heel cushioning to be right on the edge of being too soft. We imagine that most folks who are fans of the 2100 series won't mind a little extra cush, and the shoe still remains responsive overall for a high-mileage daily trainer.
It's hard to find complaints in a shoe so carefully designed to appeal to a wide range of runners. The 2170 will be a popular choice with runners who are just starting out along with veterans who trust this model on training days.
The Gel cushioning in the heel is definitely beefed up a bit. I can't see Asics dialing in much more cushioning in future 2100 series models.
Runners who liked the 2160 and prior versions are going to feel at home in this shoe. I'm impressed by how much the build quality has increased over the 2160, and that certainly was not a poorly built shoe.
If I was given $100 and told I had to buy a pair of running shoes with it, the 2170 is hands down the model I'd choose. This shoe deserves its popularity.