http://www.madebyknock.com/store/p50/Aerspeed.html
The Aerspeed actually. I got mine for £75 at an event in London, which is how much he's selling them for before VAT. So £90 (unless it's a business expense

)
It's more suitable for most types of home brewing coffee - essentially its very similar to the Aergrind, but the burrs are calibrated more toward filter coffee, with deeper cuts in the burrs themselves (which also means a faster grind time - hence the name). What this means is that it has more adjustment throw (ie is easier to adjust) within the kind of grind sizes used for filter-like sizes - pour overs, french presses and that ilk.
The Aergrind should be a bit better toward the espresso end of things (but - it's really not going to be a great espresso grinder, even though it's technically capable of producing an espresso grind - it'll be very tough to dial the fine grind size adjustments needed). The aerspeed works well with my aeropress, but I know some prefer a very fine grind that's closer to espresso than french press on their aeropress - so possible the aergrind would be better in those cases. Basically the aergrind is a slightly "better" grinder, because the burrs aren't cut as deeply, which produces less fines,
yet it might be
a little tougher to adjust to the ideal grind size - but for home brewing, those differences can be theoretical rather than observable (I haven't done a test, of course!)
The aerspeed uses the same housing as the more expensive aergrind, but apparently they assemble the aerspeed with the "less cosmetically appealing" housing parts to keep it's cost down. Aside from the different burr cut profile, the burrs also aren't treated the same, and may not last as long as the Aergrind burrs (again, keeps costs down). But Peter told me the Aerspeed should do at least 200kg before one needs to think about replacing the burr set on the Aerspeed..
To be honest I couldn't understand why they had both the Aerspeed and Aergrind in their line up - there seemed to be too much overlap between the two products.
That was probably a lot more information than anyone wanted.