Ok, so I've only had this out a couple times, but I figured I've learned about everything I'm gonna "learn" about this club. The rest is just practice and (hopefully) improvement.
I first saw "The Little One" at Golf Galaxy a month or so ago. I asked it if was for sale (it was in what looked like a demo bag of sorts near their workshop area where they work on clubs), but was told it was not. I snapped a couple pics and went away to eBay to find one for myself. Picked one up for <$30 after looking for nearly no time.
http://www.ebay.com/itm/Pure-Solid-Perfect-Mens-The-Little-One-Golf-Club-Training-Aid-RH/292174469619?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
So, the concept is simple. This thing is small. No, I mean, it's very small. A quick Google search will turn up more pics. The best pics are the ones that show it against the outline of a "normal" sized club with the outline of a ball in front of The Little One. The clubface is barely big enough to hit a golf ball without toeing it or shanking it.
The first time I took it to the range, I thought I'd just wasted $30. I must've hit 30 or 40 balls with it and I don't think anything over a 1/4 swing was yielding acceptable results. Shanks, toes, etc. were all there were to be found. So, I put it away and figured it'd take a while to get in the groove with it.
I've always been able to find the center of the clubface for the most part... left to right. My misses are generally up and down, fat and thin, so I wasn't too worried about this club and, honestly, didn't know if it would really help me greatly. I was wrong. As much as I thought I was finding center of the face, I was off. This club reveals all.
The second time out on the range, I started with little 1/4 swings. After maybe 5-10, I moved up to about a 1/2 swing. Even that felt good. I was making pretty good contact with it. Moving past 3/4 swings I made few mishits. I was amazed that this thing was giving me good distances. Just a little shorter than my 7i. It's about the same length as my 7i, 37", and from what I can guess w/o a gauge, about the same loft, too, though it might be stronger since my lofts are likely weaker than most nowadays.
All in all, I'd say, if you're willing to hit the balls to get this thing to work, it's definitely worth a try for $30. I don't see selling mine now that I have it.