I was really nervous about 1/4" positioning when I got my
b2920, but now that I've used it quite a bit it's not such a big deal. It does seem like very heavy implements may sink just slightly over time, so I just bump it every 10 mins or so to keep it at the right height and its a non-issue. Re-setting height is harder to do, but I find that the things i do don't require so much precision that it matters, its pretty easy to get it 'close enough' and not worry about it. If I were offered position control I'd be happy to take it, but I don't feel like I'm suffering at all without it. (It may just be that I don't use implements that require that level of fine grained height adjustment)