I have been using version 3, downloaded from the site and it really has been the best window switcher I've ever used. I've used Witch for a while and Hyperswitch as well, as I'm a keyboard-productivity fanatic. But neither suited my needs because they would not show certain app windows.
Then at one particular moment, an issue started that froze Contexts when switching fast. Luckily the developer has been working hard to get to the bottom of it: the 'end of trail period' message was interfering with the panel when switching really fast and this was causing the freeze.
This is really the most positive and fast experience I've ever had with a developer to help out and improve his app.
Moreover, he has promised additional interesting features coming up, it is nice to know the app is actively being developed since Apple does not sit still either.