The NuVinci drag is certainly more than that of derailleurs and more in the hub gear region, not just my impression but also that of hugely experienced cyclists David Henshaw of A to B and Peter Eland of Velovision. The big difference from conventional hub gear drag is the the NuVinci is consistent throughout the range, so when ridden and accustomed to it there's no change in drag like that at different gear range points in geared hubs. So the NuVinci feel is very much like that of derailleurs which are also constant, albeit with virtually non-existent drag in their case, just the chain/sprockets of any bike.