The Staples labels stick as well as Avery's but they are harder to peel off. When you are in a rush or doing a large mailing this can make a difference.
I use this size for small mailings addressed with MS word mail merge. I print a whole sheet of our address and use it for return address labels. I print a whole sheet of our address and use it for making quick return envelopes to send with bills(I don't have preprinted return envelopes).