Bisq has been around
since December 2014, with over 200 contributors and also connects through Tor by default.
However, I confess that it feels a bit more complicated than an instant exchange running in the browser.
The main problem I have with decentralized software like Bisq, is that it's
software. I prefer to install as few programs as necessary, and don't want to go through the hassle of using a VM all the time.