Thanks for all the replies everyone, this is very helpful!
@Cuprajake – I agree that pre-wetting by itself (in machines that are not plumbed in) is not sufficient to completely wet a single 12 gram puck, at least not within 30 seconds. It might be sufficient with those 7 gram 41mm baskets, but that’s not the amount of coffee I want to use normally. Pre-wetting does work if it follows turning on the pump for a few seconds. The pump is very aggressive, so it’s difficult to stop right at the moment when there’s a first drop visible. But if you turn it on for, say, 3 seconds, and then turn it off and start pre-wetting, it’s very easy to stop right at first drop. At least it is if you’re using a bottomless portafilter and a mirror.
@Alexvs – I have the funds to get the Bianca, but will only go for it if it provides enough value for the higher price (compared to the Minima and the other machines I’m looking at). The only real drawback I see with it (other than maybe size) is that it uses an E61 grouphead, and coming from a machine with one, I’m hoping for better temperature stability in my next machine. Not sure if the lever-less Minima is better here, but I know the Elizabeth and BDB definitely are.
@Rob1 – I think the middle position is actually useful (see explanation I wrote above about pre-wetting to Cuprajake), but it’s not a must. As for backflushing, the water can’t go anywhere in this position because both valves are closed. It does allow to maintain full pressure for quite long (I usually hold it there for 10 seconds) without straining the pump. I’ve been doing it for a long time with my Quick Mill Alexia Evo with no adverse effects. But just like pre-wetting, it’s definitely not a must have feature.