structurally, there's nowt to choose between yorkstone paving and block paving for a residential driveway, assuming top quality materials are used. A properly laid yorkstone drive will give you at least 25 years of service, as will a properly laid block paved driveway.
Maintenance-wise, they are both similar in that they need cleaning and weeding once a year to keep them in prime condition, although you can minimise this wth the use of a quality sealant.
But cost-wise is another matter. Best quality reclaimed yorkstone will set you back around 35-40 quid per m2 just to buy the flags, whereas you can have rectangular block paving completely installed for that sort of price, or a few quid more. New Yorkstone is even more pricey, but there are cheap imports now on the market at around 20-35 quid per m2. There is, however, some concern about the quality of the real 'bargain' priced stone, though - see other threads.
Another consideration is that yorkstone is known to 'walk' overnight. Because it has such a good resale value, the drive bandits are always on the lookout for a nice yorkstone driveway that they can load onto their wagon while you're on holiday or away with the caravan. Block paving is much less likely to be stolen.
At the end of the day, it depends on your personal taste, your budget and what sort of property you have. In my opinion, there is no better paving for residential driveways than block paving. It's relatively cheap, it's easily maintained, it's attractive, it's easy to repair. There are indeed some properties where Yorkstone looks better, but for 9 drives out of 10, block paving is a better choice.
I wonder if this contractor is pushing you towards yorkstone because there's more profit in that for them than there is in block paving? Why not get them to price both options and we'll have a look at their specifications, if you wish.