I second the recommendation for the Shutter Precision 8 series hubs. Extremely comparable to SON, at less than half the price. They come with a 2 year warranty, which is fine considering the fact that they cost right around 2/5ths the price of a SON, which has a 5 year.

From the few reviews I could find online, and the reviews in BQ (which are to be taken with a grain of salt, as BQ is as much advertisement as reliable information source), they have very much the same resistance both on and off as the SON 28. The SP hubs are a bit higher drag than the SON deluxe, but the deluxe also has significantly lower power output (it can drive a light, but it's not enough to power USB devices, simultaneously). I think SP also has a SON deluxe competitor (i.e. a hub designed for 20" rims), which would likely have very comparable resistance to the SON deluxe, if that's your choice.

I can't honestly recommend a SON to anyone with SP hubs available, as I highly doubt the SON will out-last a SP hub for enough to make up the price difference.