I own and use one of the Scorpion antennas, the shorter version. I can tell you that it works well, on 11 meters too. I don't own a Wilson antenna, so take this for what it's worth. The Scorpion will out perform that Wilson on any band other than 11 meters, simply because the Wilson was never designed to work anywhere other than 11 meters, no matter what you think it's 'bandwidth' is. I don't think the Wilson is a comparable antenna because that Scorpion is longer (on 11 meters too).
Having said that, the Scorpion would not be my first choice for a strictly 11 meter antenna. I think I can give you at least 500 good rea$ons why.
The Scorpion is not a 'plug-n-play' antenna! It does require some setup. It also requires a very, very heavy duty mount. That antenna is heavy. For get a ball-mount, or a 'puck'. Do some checking as to how the thing is mounted before getting one.
Can't say much about the "fixed" mounting system, I don't have one. If it's -anything- like the antenna, it ought to do as well as any mobile antenna used as a fixed antenna.
I've seen several of the other screwdriver type antennas at one time or another. I can honestly say that I've never seen one that will compare to the Scorpion's quality. You have to see the thing to believe it. A very good indication of it's quality is the way it's shipped. You have to see that to believe it too. Follow the instructions for unpacking it! Otherwise, you won't get it unpacked.
I've used a bugcatcher antenna for a very long time and as far as efficiency I don't think there's anything that will beat it, bar none. The Scorpion comes closer than anything I've used/heard so far.
Enough of all that. Best choice is the one that fit's your situation the best, and that you are willing to pay for.
- 'Doc