AH HA HA
MADE YA LOOK!
Ok, as some of you might have guessed, I got the grip a while back and my experience has been great. Since jmeelo of DPR already did a lengthly review of the Ownuser Grip, I'm just going to cut to the chase.
WHY I BOUGHT THE GRIP?
- Heft
- Battery Power
- Extra Vertical Shutter Release Buttons
- Space for Pinky Finger (better handling in general)
"ISSUES"
1) NO SIDE DOOR COVER
This problem is 50% inherent to K100D's design having no electrical contacts in battery chamber nor on the bottom of the dslr. The other is Ownuser's attempt to save costs making one universal grip design and then just making camera specific base plates. Its too bad a cover was left out but the open door was not a big problem for me.
2) NO AE-L, DOF, JOG DIAL
This is because Pentax again, did not design K100D with a battery grip in mind so no contacts were designed for communication of mentioned features.
3) WEIGHT
How heavy is the K10D's D-BG2 grip again? Or the Canon and Nikon Grips? If you mount a loaded (12 NiMH AAs) Ownuser grip, tack on 600g. Camera + Grip + Lens = alot of strain on neck.
4) QUALITY
All in all pretty good. Just be careful when loading/removing the batteries. The AA clips don't feel too sturdy. Do support lens if using a heavy one. Remember the Grip is attached only by the tripod screw. The camera base plate on the grip that the K100D sits on doesn't feel like it could withstand rough handling.
***FINAL NOTE***
It seems like for
so many of you, the lack of the side door cover has been the deciding factor in the purchase of the grip...here's a economical* SOLUTION.
(*depends on what product you choose.)
SLICK...EH?
The solution was just a cheap L Flash Grip from Ebay. (Just make sure you get one that's tall enough. The height from the base of the grip to the neck strap collar is 11cm or about 4.5 inches.)
A two birds with one stone approach for those interested or use flash slaves! You've not only installed a protective measure for the side door but provided another place to mount a external*/slave flash! (Just note that because of the screw head on the L grip/frames, the K100D + Grip + L Frame setup no longer likes to stand up straight. It likes to tip over.

)
*You'll need some way to sync like some adapter cord.
HOPE THIS SHORT REVIEW ALLEVIATES/ANSWERS ALL THE CONCERN REGARDING GRIP SOLUTION FOR K100D! =D