I'll add some additional observations. Mine arrived today and so far I like it a lot. Key press is much better than I anticipated, and I think Jeff O. described it pretty well: firmer keypress than original, but not as nice/smooth, yet still very respectable.
I get no key rattle at all, and while the colored function keys do drift a little, they're not bad, and I probably only noticed this because it was mentioned here. The display is great, basically identical to the vintage 15c display, with maybe a slightly (as in very slightly) yellowish tinge.
Cosmetically it's an almost-perfect reproduction. I'll concur some of the other points: the yellow labels are a bit brighter, making them easier to read. If one really scrutinizes, you'll find that the border around the edge of the keyboard is slightly thicker, and that the "HEWLETT-PACKARD" branding on the bottom is bold Helvetica instead of plain. (And now the label runs to the near-end of the RCL key instead of to the middle.) And comparatively, the LE's plastic case is more black than then vintage 15c's brown.
If you stand them on a desk side by side, the LE stands a tiny bit higher (1mm, maybe 1.5mm), and I can see that the LE is more uniform in thickness (in that the original 15c has more of a taper toward the front/bottom edge). I first attributed this to the fact that the LE has thicker feet pads, but upon inspection it actually is thicker, especially on the front/bottom edge.
(I suspect that this is the same physical form factor as the modern 12c calculators, but I don't have one to compare.)
The back side of the calculator, of course, looks totally different. The big metal label (with error codes, &c.) is silver instead of black. I personally find this contrast jarring, but nothing substantial to complain about. Also, the brushed aluminum bezel on the front is different ... it doesn't actually feel like brushed aluminum in that it's totally smooth.
All in all, I think it's great. HP, this totally made my month. Many thanks.
For full disclosure, I do have one complaint thus far, which is regarding the slipcase. It's fractionally too small for my calculator (both in width and length) and irregularly sewn. Even when I fight the calculator all the way in there, it sticks out of the case by about 3mm. Just by trying to force the calculator into the case, one of the seams at the opening has already started to come undone. Annoying, but not a big deal, especially since I think I have a spare kicking around in the office.
Edited: 16 Sept 2011, 10:28 a.m.