In all of the promotional materials for this product, there was a focus on the ease of detaching and attaching the bottom sole piece. It looked like you could step into it, press your heel down, and click into the additional piece. This is not the case at all. The bottom piece is very difficult to get on, I have to step into it, prop my foot onto a chair, and use by fingers to dig the rubber lip into the attachment. Is it strenuous? No not really. Is it inconvenient? Definitely. Is that what I signed up for? Not at all.
On top of that, the design for the foot is a terrible fit! There's no support around the heel, so with every step my heel is sliding in and out of the shoe! I have the right size, it's not too big and there's no "room" in the shoe that is making it do that. It's the fact that the rubber attachment on the bottom is quite rigid and the shoe doesn't tighten around your foot, almost creating a flip-flop kind of effect. With socks, it's bad. Without socks, you pull the insole out when you remove them. Not a fan.
The detached mode is alright I guess. The thin sole is more flexible which eliminates the heel slide effect. But it's become almost obsolete to me because of the inconvenience of going in and out of the "outside" mode.
Look, I bought this product thinking this would be a super fast and convenient way to wear shoes that can transition me from inside to outside by stepping in, pressing down, and carrying on with my day. But they're more inconvenient to get on and off than my Nikes, so I just opt for the Nikes. They're not that comfortable, they're very expensive, and they're very inconvenient to use.
Please save your money.