^
Mr TF and I were only having this debate this afternoon, having looked at the site. We've not encountered cassettes before so can't really give an opinion. It certainly sounds a nicer system than pump out. And you're right - go too long between pump-outs and things can get a bit pongy.
And yes, use other people's loos whenever you can. Same goes for showers! I remember there was a place in Stratford on Avon where you could go to a public shower.
Having said that, the facilities look great so you shouldn't want to do that.
Oh and dump rubbish too whenever you can.