When I purchased the Pentax K7, I agonized over which battery grip I should purchase - the Pentax BG4 or the Chinese knock-off available here and on the auction site. I went with the imitation and, never having used the real Pentax, it seemed adequate. But I had issues - the silkscreened button labels rubbed off, the rubber veneer began to peel back, and the wheel and buttons were wobbly and cheap feeling.
After purchasing the Pentax K5, I decided to get this grip - the real Pentax BG4. What a pleasure it was to take this out of the box and wheel it onto my camera. The fit and finish are impeccable and the button/wheel action mirrors the camera's own. It's also worth noting that the rubberized sections have a nicer look and texture. I believe this product will last a long time.
For those on the fence regarding either the genuine or counterfeit grip I recommend the genuine artifact. I sympathize with you regarding the high cost but, then again, you did purchase a $1500 camera.
Final notes:
- The grip is plastic, not magnesium alloy but is tough, well-balanced and feels like the latter.
- The grip is waterproof whereas the imitations are not
- The tripod mount thread is off-center as it is on the imitation.