Quite a timely thread for me ... I recently spotted an electric screwdriver at the local flea market and got it for £7. (The stallholder's pal laughed when I agreed to pay that price and said I could have got it for £5-6 if I had haggled!)
It had a Philips bit and I had a big box of Philips screws which I was using to fix some plasterboard up. I knackered the bit within about 10 screws so I have decided to go Posidriv from now on. I found a company on
eBay doing a bag of 10 PZ bits for a few pounds so I'll give them a go. They might turn out to be cheap rubbish but it seemed worth a punt.
I hadn't realised that there is actually a significant difference between the 2 types of head until now which is a bit odd (sorry for the pun!) given that I worked for several years in a factory and averaged about 1,500 screw insertions a day using a compressed air-powered screwdriver. I can't remember which type we used, but suspect that they were PZ because it was very rare for the bits to slip. We only had problems with snapping the heads off after the company buyer tried to save money by buying crappy unbranded screws in bulk rather than the quality GKN screws that we normally used.