My two'penneth worth.
We got almost 40k miles from the original Conti Van Contacts 215/60 17" 107/109.
Went for Conti All Season Contacts 2's at 235/55 17" 103. Paid £660 for all four at our local independent tyre place. They're 3PMSF rated.
Thus far - noticeably quieter, slightly softer ride and less harsh. The speedo seems to be more accurate, but this could be down to a new tyre having a greater circumference than a worn one. Economy doesn't seem to be affected, but it's been a cold and dark period of driving, quite laden over Christmas etc so this needs more miles to verify. I'll report back.