In SBSettings, do you have ‘More Sensitive Swipe’ turned on? Try turning that off if you do.

Tried short swipes left and right, and short swipes up and down. Not happening for me at all with your setup. I either get both mQucikDo and SBS popping up every time, or I lose the ability to get to SBS – way, way too irritating. I prefer the bar at the bottom – but I prefer for it to keep working steadily.
Anyway – I like the app enough to keep it for now. If it continues to be this flaky and does not get an update, I'll likely ditch it and just use Kirikae.

Which gestures do you use? I disabled most of the mQuickDo ones. All I use is swipe down. So for SBSettings I swipe to the right, for mQuickDo, I swipe down.

Hmmm – I like the sound of how you have it setup, and I'm trying it out – but so far no matter what gesture I assign to it, I get both mQuickDo and SBSettings popping up when i try it. That's no good because SBS stays up when I switch to an app.

It could be an issue with Winterboard I suppose, I do use Winterboard and the Glasklart theme – but it would be very disappointing if it has any sort of unsolved conflict with such a 'mainstream' (in jailbreak terms) app. It is tough to troubleshoot an intermittent issue, for sure. I would find it much more promising if their support folks seemed to have any interest at all in resolving any of its issues.

I like Kirikae as well, need to do a post on it at some point. I think this is – literally – one of those areas that is very much different strokes for different folks. When it's working, I much prefer mQuicko's swipe gestures on the screen to having to mess with the home button. But they really do need to make it more stable – I only find it intrusive of late because of its flakiness.

Gestures are cool, but mQuickDo sounds too intrusive to me for a task switcher. Kirikae gives several options to engage (I prefer press and hold home), and there's a favorites list. And it's not at all buggy (in my experience). All in all, hard to beat for free.