The best answer I can give is to buy only a couple of rolls, test them and then buy the whole lot if you like it.

I prefer to use fresh film but here is my experience regarding expired HP5:

3 years expired, stored on the shelf of a shop (20-35 C): high base fog and lowish speed.

28 years expired, stored on the shelf: the same as above, but it wasn't as much worse as I had expected it to be.

Give it a try, you might like the result, but don't expect miracles.