The basic NV and the vineyard selection "Crede" are both off-dry with an attractive floral character and about 10 grams/litre of sugar and sell at around 8 and 11 pounds respectively. Worth paying for the latter although the former is perfectly drinkable.
The more expensive wines are very much towards the sweet end of demi-sec: the special selection Garnei and the Cartizze (which is by reputation the best area) run to 20 and 25 grams per litre respectively. Both seem nicely balanced wines with some complexity - the latter particularly interesting enough for me to fancy drinking a bottle properly some time and giving it some serious attention.
Champagne of course is the elephant in the room - impossible to avoid comparisons whenever sparkling wine is discussed. Well, I'd sooner drink the Crede than try and find something interesting among supermarket Champagnes. I feel the fact that it's made on a human scale with care and attention shows. The basic wine is a very serviceable sub-Champagne fizz too. The Cartizze retails around 17-18 pounds - an amount that will get you a good grower's Champagne. I think nine times out of ten I would have the Champagne, but the Prosecco is something different, sitting somewhere between Champagne and Moscato in general style and with food that suits sweetness or on a Summer day in the garden I might prefer it.
The sweetness thing is worth a little thought. I feel the
quality of the Prosecco grape might be a bit exposed if they were
made bone-dry and also that the sweeter wines carry their sugar
content a bit more graciously than sweet Champagnes usually do.
I liked these wines and will look out for them in future.