I've had all of them. The Shimano DH-3N80 is my favourite but only available NOS now. The original SON 28 was fine, but is and was ludicrously expensive. I found less lights-off drag with the Shimano (once the bearings were properly adjusted). I have an SP SV-9 on the Raleigh Twenty. It is cute but the flanges are a bit narrowly-spaced for a bigger wheel.
this is quite an old graph now (from shortly after the SONdelux was introduced I think)
I've seen other tests in which the DH-3N80 shows differently vs the SON models and I think this is because the bearings in the DH-3N80 were not correctly adjusted or lubricated. I have often had to back off the factory setting by about 1/4 turn on a shimano hub, which must mean the bearings are grinding themselves into oblivion otherwise. IIRC DH-3N80 has double lip seals which will drag noticeably if they are new and badly lubricated.
The other notable feature of the graph above is that the performance of the DH-3N30 model differs primarily from that of the other hubs in relation to the lights off drag. Again I suspect this is largely because of the bearings and mainly to do with how they are adjusted/lubricated. In terms of additional power in for electricity out, it is pretty much as good as any of the others.
cheers