I also received my Jel Tec. I'll do a pictorial comparison later but some differences compared to my Concealment Express:

Retention: The C.E has an audible click when inserted fully, while the J.T. doesn't. The J.T. had a more positive lock in after adjusting the rubber tension stoppers so that the outer is loose and then tighten the inner tension screw (C.E. only has 1 tension screw), still no audible click but much better (not better than the C.E., better than initial retention before adjusting) Both secure the pistol properly. Minor win to the C.E for the audible click.

Coverage: I did like the fact that I can eject my mag with the C.E while the J.T. covers the button (I eject my mag when I get home and put my Shield away). I can see why this would be important for accidental mag release, but it's never happened to me. It doesn't matter though. I can always remove the material on the J.T. if I decide I want access to my mag ejection button.

The C.E form fits the Shield much better (it even forms to the slide's scalloped grips) which adds to that audible click. The C.E molds to the take down lever, slide release lock, and thumb safety individually (I have the no safety model) while the J.T molds a single channel for all 3. You would think the C.E would be preferable but those 3 bumps create pressure points against your body whereas the single channel mold of the J.T distributes pressure more evenly. The J.T. mold covers the rear sights so no more jabbing in my side. The J.T's less-precise mold makes for a smoother surface against your body whereas the more-precise mold of the C.E. makes for pressure points. Win to the J.T.

Belt Clip: I like the J.T. better as it's mounted closer to the holster and doesn't stick out as much. J.T. sent me both belt clips at no charge (I had to request it). The J.T. has a flat surface to match the belt clip area whereas the C.E. belt clip doesn't.

The biggest thing I noticed and the deciding factor for me: The J.T's belt clip is mounted higher so that my gun now rides about an inch lower on my hip than the C.E. It's so much more comfortable and my gun doesn't shift as much because of the lower center of gravity. Yes......yes I know a proper gun belt would help with shifting and weight distribution but convenience is #1 for me. Maybe I'll eventually get a gun belt but for now the J.T is way more comfortable, really noticeable when driving (I have an 8 hour trip to Yellowstone coming up). In addition, the J.T. conceals better both from the less-visible clip and the lower ride height. You can't beat the price and service either (C.E. had good service as well but costs twice as much).