I know how you feel, I was in the research phase 3 years ago :)
DVBSky cards: I have one DVBSky S950C, which I don't use. If you'd like, we could make arrangements if you want to experiment ;)
However, my experience was that it is fine for receiving Astra 19.2e, which has an extremely strong signal, but it goes downhill pretty fast from there. I haven't tried with newer kernel versions (drivers). It did work out of the box though...
To be honest, about the octopus bridge, I"m considering buying the bridge and two expansion cards only because I want to stick it into a minipcie slot. If I was putting it into a PCIe slot, I'd go with a regular tuner card and expansion cards. Mainly because it is cheaper...
If you have completely ruled out TBS cards (which, as I said, work fine in my box), then IMO you should to go for digitaldevices. With which I have no experience, ironically.
FYI:USALS is just a combination of Diseqc 1.2 and angle calculations. So if a tuner supports Diseqc 1.2, USALS is on the software. And tvheadend does it fine.