I think a civil discussion of comparable apps' relative merits benefits both the users and the devs. We shouldn't be afraid to honestly relate our actual user experiences, which any intelligent dev should find quite valuable and not something to get defensive about. The devs can improve their sense of what the users want and need, and they can compare with other implementations to think of better ways of doing things. Abusive users are another story, but that's not us.
I've paid for both Alfred and Launchbar. When it comes to app switching, Launchbar is the clear winner as its interface is much faster (i.e., requires many less keystrokes) than Alfred. So this window focus problem is really unfortunate, but I don't experience it because I use fullscreen only rarely. Launchbar is having the failure-to-launch problem discussed in another thread when using a single tap to activate it, so I'm forced to always activate LB via cmd-space until the problem's fixed. I type fast, so a failure-to-launch leads to clobbered data, but cmd-space is two keystrokes compared to the single tap, and this matters to my in-the-field experience. Alfred is unacceptable to me as an app switcher because of its lack of abbreviations: there's always some chance--however small--that a given keystroke sequence won't launch the app you intended, greatly slowing down my speed.
Karabiner is the last word in the absolutely fastest, most customizable app switching, but its re-design for post-El Capitan kernel changes is still not complete and all the basic functionality for app switching still isn't available.
By the way, as the Alfred devs point out, Alfred's different design philosophy makes it far better than Launchbar if you need to do a lot of serious file searching across many volumes, particularly when they're on other networks. I never need that because my files are organized in a way that LB always finds what I'm looking for quickly. I've used Alfred and LB concurrently on the same machine, and that works fine, but lately I've turned off Alfred because even though Alfred is a great app, LB does each thing I actually need to do faster, plus a few things Alfred won't do at all, like Sending.