Pilkington windows - Self clean?

[car]

Following on from my other windows post. At the ordering stage, anyone know if [broken link removed] with the self cleaning feature is worth getting? Sales guy says its very good on some houses but said its up to ourselves as it depends on house location, house facing direction, weather etc., as to its whether it would be worth it over time.
Cost about 600e extra on an 8k quote. Anyone got any experiences with it? dont think the feature is out that long from googling

 

[ted]

I have it on some roof glazing. I can't really see if it is any better as I don't have a comparison. Bird poos do come off though with the rain but would they have anyway I wonder. I certainly would bother doing it with vertical glazing though. No need unless your planning on having non opening windows that cannot be cleaned easily from a ladder or from inside.