Ok this might help some who are wondering, finally made the move, and upgraded my v1 500GB (1st gen) TC to a 4th gen 2TB. The Time Capsule has its own FCC cert - BCGA1409, model A1409, so I believe it does have a similar radio change as the AEBS. I don't really have a terrible/bad location for signal strength, but testing 3 positions between both units, there is definitely a slight improvement (looking at 5 GHz RSSI)... both TCs with wide channels and a late '2010 MBA max out at 300mbps (no 450mbps mode). The big change is file serving speeds. The following is wired (GigE) with Windows 7 Robocopy/SMB... 1st Gen TC (Write) Speed : 15621111 Bytes/sec. Speed : 893.847 MegaBytes/min. 4th Gen TC (Write) Speed : 31179838 Bytes/sec. Speed : 1784.124 MegaBytes/min. 4th Gen TC (Read) Speed : 31522685 Bytes/sec. Speed : 1803.742 MegaBytes/min. Synology DS210j Mirrored WD15EARS (Write) Speed : 28190869 Bytes/sec. Speed : 1613.094 MegaBytes/min. Synology DS210j Mirrored WD15EARS (Read) Speed : 63334819 Bytes/sec. Speed : 3624.047 MegaBytes/min. Did not test read speed of the 1st gen, but this is a 2x improvement in speeds, and its even a bit faster than my Synology 2-disk NAS with mirrored drives (the mirroring does slow things a slight bit) with write speeds. But the read speeds are pretty similar to the write speeds, unlike the much greater read speed I can get my from Synology NAS. All in all its a pretty nice performance bump/upgrade from a 1st gen (not sure how the 2nd/3rd gen TCs perform). Edit - seems like this one gets pretty hot too, just like the old one did.