This is my main problem as well - the house sparrows are downing suet like crazy this summer. I can't stand those freakin birds. I put out sunflower and they hog it, along with the monk parakeets. By the time the blue jays and cardinals come along, the feeder is empty.
I had a suet house which I removed early this morning, before the birds were even awake! It was too easy for the sparrows to use it, and they were attacking the downies. I replaced it with the regular old suet basket, and the sparrows seem wary. For now. The downies are fine with it, but I had also wanted to try the upside down feeder, and have been going crazy the last few days trying to find one at a decent price. (Seriously, $25 for a feeder is ridiculous.) Some of the prices I'm finding online are decent ($15) but everyone gouges on shipping.
I'm going to try this setup for now. Maybe come fall, when stores are stocked for winter feeding, I will find something reasonably priced and try it. For now, because of the sparrows and parakeets, I only fill small feeders a couple of times a week. Those brat birds will make me go broke!