I agonized over this decision for two weeks until I ordered the D10 combo pack from 4sevens last night. I still haven't gotten it of course, but I'll tell you why I decided to get that over the EX10.
There are three main reasons I opted for the D10. The first being the 14500 batteries from AW seem to perform almost the same as the AW RCR123 cells. They are both 3.7V and 450mAh. Most of the light readings I've looked at gave both lights on the AW rechargeables very close Lux readings. At least as far as I could tell. The rechargeables definitely seem to give more output than alkaline AAs.
That brings me to the second reason, I can get AAs anywhere. Lithium AAs are also available if I need cold weather performance and the run of the mill AAs are there for emergencies. I have a few CR123 based lights, and I've got a small stockpile of cells, but after losing power for 6 days recently the common AA started to look pretty good.
Lastly I saw two pictures here on the forums of EX10s that had broken or right at the base of the male threads. I had initially wanted an EX10 because the stainless bezel ring made it look stronger. When I saw the pictures of the broken lights and noticed how thin the metal is in the grooves on the head I had to pause. Looking at the pictures I could find online of the D10 with the head off I realized that it has the male threads on the body of the light and they looked like there "might" be more metal there. I won't know for sure until I get it in the mail. It isn't going to be a lot of difference, but it may not need to be. I haven't seen any pictures of broken D10s. This may be flawed logic, but I'll see.
If I really love the light I may go ahead and get an EX10 also anyway, because I believe that 4sevens will stand by his product. I'm actually just hoping they will come out with the next generation with a slightly beefier construction.
Then there was the question of whether or not to get the Cree or the Osram GDP...
