I thought long and hard and read much on this subject, and ended up with a Loricraft PRC6. Very quiet (it's feasible to listen and clean at the same time which you can't do with a Moth - which I had prevously) and works extremely well.

If I had the dosh I might be tempted to have an ultrasonic for occasional use for really problematic records (finishing them off on the Loricraft) but there seem to be too many questions about them for daily use.

I'm delighted with the Loricraft.