How well does the 'Katz Eye' focus screen work?

I've seen a couple posts where Katz Eye was mentioned and have wandered over their website.

Anyone have pros/cons about focus screen replacements?

I know I need something to help make manual focusing faster than the standard screen.

Thanks.

The Katz Eye is an excellent way to aid manual focusing. I use one on my K10D, it would be very hard for me to manually focus without one.

It is designed to replace the screen that comes with the camera. Unfortunately, Pentax does not make a manual focusing aid on any of their replacement screens, so the Katz Eye is perfect. It can be ordered with any number of markings, or none at all. Highly recommended.