Okay, so this has been idle a while... I have two different strainers/food mills. The first is a Foley-style hand cranked mill. It has plates with different sized holes. The other is the grinder/strainer accessory for our Kitchenaid mixer. Both work well. The texture with even the finest hole plate in the Foley is more coarse or rustic than the Kitchenaid. I like them both. The Kitchenaid probably gets more juice and pulp and is a bit less work. It is also 2-3 times more expensive (if you have the mixer).
I bought the Kitchenaid strainer this fall and used it to make a ton of apple butter. Sure cut the work by 75%. And gives me one more thing to use my Kitchenaid for. Well worth the 49 dollars I paid for the attachment!
I ran the apple peel/seeds through twice and there was very little waste when it was over. All I did was quarter the apples and take off the stem. Didn't core them.
I used it on pears but the skins of the pears that i had were very tender and some of the peel was pushed through the sieve. That wouldn't be a problem unless they pears were a bit spotted and you didn't want flecks of brown in your jams. Didn't run them through twice. I think they don't recomment it for blackberries if I remember correctly. I think that's because most of the juice is pushed out of the berries and the seeds clog up the worm of the sieve.
After using the grinder/strainer combo for a while I can unreservedly recommend it. It makes great applesauce and great tomato sauce. I was also able to separate a good deal of juice from the sauce, so the work yielded sauce and juice. I also now use the grinder for all our ground meat. I buy "market pack" brisket for about 1/3 the cost of hamburger, then trim and grind with exactly the fat amount that I prefer. It also does a great job grinding chicken or turkey and I use it to grind all the meat for homemade sausage. I've made normal sausage patties, bratwurst, smoked sausage, and Cajun andouille.