Checking some photos last week, I noticed a couple spots on all of them. So I made some test shots to see how bad is it. The result: 4 nasty spots
+ a few not so nasty
Took out my blower and gave it my best shot, but with little success. The dust was still there, it just migrated.
I didn't have any cleaning kit or such, so I checked the internet to see what can I get.
As you said this is supposed to be the official Pentax sollution and it looks so simple to use. Bought it this saturday and used it the same day. Made a test shot. Still a couple minor spots visible. Took another try and got rid of all but one barely noticable spot.
I'm happy with the job it did, so I say go for it. Just make sure you don't use too much pressure.