Of my work, I usually use the mastered mixes right from the releases they are on when I make 'samplers' to hand out in bulk.
If it's a band I am really trying to get a big deal project with I will just give them copies of records I have done that I think the band would like. Nothing sells you better than when a band sees a finished product from another band that looks sharp, sounds sweet and has that 'this should be on the shelf at best buy' feel to it.
Bands are always motivated more by the end product. Give them finished product that they can see, feel, touch and experience. It eliminates the need for trying to educate all the bands in my town about what mastering is and why the mixes aren't 'loud enough'.
Just my thoughts on the matter.