John,
I like the shape; in fact, I've made some with similar shapes. To me, a standard slimline is too thin to write with comfortably, and I think that's true even for most adults with smaller hands. By giving the lower barrel a gentle curve, you've thickened the barrel and given the user something easier to hold. Your finish certainly looks good in those pictures, too!
My only other critique is that you appear to do like I do, and simply make the ends of the barrels match the bushings. As you can see from the left-hand most pen, this can sometimes lead to the tip not QUITE meeting the end of the lower barrel (i.e. over or under-turned barrels), and even some differences at the CB and finial. If you were to use a micrometer, or even stop the lathe and do a "dry fit" of the tip, you'd probably get more accurate results (again, this is something I need to remember to do, too!).
The tip end is the one about which I am most concerned, since that's what the user will be touching most of the time. Some people like to leave this a little "proud", so there is some room for the user to gradually wear the wood down. If this was a conscious choice on your part, then feel free to disregard my comment! (Actually, feel free to disregard anything I say!)