Its around four weeks since I had the 4 mismatched tryes replaced on my CRV and the difference is noticeable on the ride and steering. I've used Avon before on my transits and been happy with them so when I was offered 4 at a very good price I went for it.
Think they thought I was mad as the old tryes had plenty of tread left but I hated having 4 difference make of tyres and the price won't come again!!