Seriously, this is really useful info.
Last time I had to replace a windscreen (W169 a-class) my insurer wouldn't replace with a dealer or even OEM screen. This seemed crazy to me, the car still being under original Merc warranty. Since there was only 3 months left on the warranty I accepted the default autoglass screen made by chinese outfit "FY". I've actually had no problem with it. It cured an annoying squeak, rain and light sensing still works fine.
If I'd known how much I could have got a Pilkington (OEM) screen for, I might have taken the token contribution offered by the insurer instead of the screen (£150.00 iirc).
It's hard to shop around when you're screen is badly cracked, feels like a bit a of a race against time to sort it before the thing crazes and you can't drive anymore.