I've just looked at several of those fonts, and (like every other Free font I've ever seen) they are all unusable without antialiasing, which makes them worthless for on-screen use to me. It's like they have no hinting at all, though I'm aware that good hinting is very hard work, so I expect they've been hinted, just badly.
I've never been able to understand the obsession in the Linux world with having large blurred fonts. A default install of Ubuntu makes my eyes start to hurt within a few minutes from desperately trying to focus on blurry text, but turning off antialiasing means I have to download msttcorefonts in order for text to look even remotely decent. When I was using a CRT I assumed that the people who designed these things were using monitors that rendered them completely differently, but now I have a fairly expensive flatscreen monitor it looks even worse, because everything else is sharper.
Am I seriously the only person in the world who wants on-screen fonts to look sharp and crisp like they do when using most non-Free fonts?
(Exception: Terminus and a handful of other Free *bitmapped* fonts are extemely good)