Linda, re. "loads that are not full...." I have a Really Dumb Question.
Are you saying that a proper full load is 100% of the volume of the drum, uncompressed?
When I've used FLs in laundromats (I don't own one, though when I buy a house I'll get one), I've always used a large one and loaded it to about 2/3 full with dry uncompressed laundry. The load compresses to about 1/2 full when it's wet, and doesn't vibrate excessively during spin cycles.
My reasoning is that at 50% full when wet, there's better mixing action, similar to mixing concrete in a portable electric mixer. The clothes get lifted and dropped into the water repeatedly, and get some rubbing/scrubbing action against each other. The way I figured it, if the wet load were above the centerline of the drum, it would roll as a mass and the clothes at the center of the mass would get less relative movement.
Was I under-loading the machines?, or was my reasoning correct?
(If I had one I could guinea-pig test it under varying conditions to see what works, the goal being to maximize efficiency and minimize wear on the machine.)
Lokimonkey, what country did you come here from?, and what types of machines are in widest use there?
Re. recommendation on relatively inexpensive FLs, there's a Danby DWM 5500 W available at Home Depot (some of us jokingly call it Home Despot because big-box stores tend to put smaller locally owned stores out of business, reducing the degree of diversity in the market). It might also be available via other dealers if you look around a bit. The Danby unit is made in Eastern Europe and has gotten good reviews on some of the consumer opinion websites, along with the matching dryer. About $400 and $300 respectively, total $700 for the pair.
Danby also has a twin-tub for about $250 with a full-length agitator and 1600 rpm spin-dry compartment. This could be a viable solution for water/electricity efficiency without spending so much, though it does require manual intervention at various points in the cycle. Widely available on the internet, difficult to find in the stores.