I found the small Impulse at Knife Center. They are asking $45. The knife has a 3" blade. Shootist16, Dennis Bible, sells knives. Sometimes his prices are lower than some of the web dealers. He now has his own website. He posts on this forum and the Spyderco forums regularly.
I own the large Impulse, and the other 3 knives. I haven't handled the smaller Impulse. But, if it is anything like the large model, it is one heck of a knife. THey have the Sandvik 12C27 (or whatever) blade steel. Not a super steel, but known for its small grain, and good stain resistance. And, it takes a wicked edge.
OOB, the Paragee was much more impressive than the EDC, to me. As the EDC has broken in, and the detente doesn't have such a terribly firm grasp on the blade, and the locking bar can be moved with one hand, most of the time, it has risen in my estimation.
I've had the LUS for quite awhile. It still strikes me as a very good knife, very well designed. It feels very good in my hand, and the blade is certainly designed for thrusts/stabs. (I think it would slash okay as well.) The action on mine has always been very smooth, and the lockup excellent. No problems with spine whack or torqueing with my hands.
The Paragee feels better in my hand than the EDC. But, the EDC has a wider blade and therefore handle as well, which I like. Though not so pronounced as the EDC's, the Paragee's blade is also recurved. The Paragee should be obtainable for no more than $40.
From my perspective, I think it probably should boil down to how much you wish to spend. I think the LUS is a fine little knife. I believe it would serve you well. Were I to have to choose from the group for self defense, it is the knife I would choose. I'd put the Impulse 2nd. The Paragee has more point to its blade than the EDC. But, the EDC is the most versatile/utilitarian knife of the bunch. With the 154CM steel, it outclasses the others in that department.
You could always buy one of the less expensive models, and if it doesn't satisfy, recoup part of your original $$ by selling the knife here -- if you're a Gold Member. Then you could try another. If money is tight now, and you expect that to improve in the fairly near future, I'd go with the LUS, then buy a different knife when you've got more bucks.
Remember this -- the Spdyerco Delica is going to be changed to VG-10 steel in the fairly near future. IMO, if it doesn't get too much more expensive, that might be the best 3" knife of the bunch.