Based on the performance of AirDisk drives on an AEBS I doubt that you will see significant performance improvement over the NextStar NAS. The Time Capsule cpu is probably the same or similar to that in the AEBS, so don't expect too much performance-wise. Remember this is a low cost all-in-one solution for home use. What we really need is for Time Machine to work (and be supported) with standard NAS devices; that is where you will see some real performance improvements.
what are the specs for throughput with an AEBS USB drive combo (or TC-USB drive combo)? The NexStar NAS is very slow... it is 100Mbit ethernet, but it doesn't even come close to maxing that out. I'm closer to being sold on it, though I have to wonder if I might be better off waiting and buying a MacMini (at the next refresh) so I can use it (and the USB connetions) for both TC backup over the network as well as for use as a home theatre (using XBMC for OSX...http://www.osxbmc.com). Might make more sense I suppose... I won't have wireless n, but maybe that won't matter so much.
hmmm....