I'd rate BB/TDK about the same and TDKR as my least favourite.
I think BB is the most watchable. I like how we see the origin of Batman, the portrayal of Gotham City is probably my second favourite to the Burton movies. The villains were ok, but probably the weakest of the trilogy.
TDK is probably the most well made of the Nolan films. Heath Ledger and Aaron Eckhardt were great. However, it does have its flaws. The action is not that great, and it does tend to drag in parts. It does wrap nicely, though, which is why I wish this was the last Nolan film in the series.
TDKR was just a chore to sit through. I do enjoy Tom Hardy as Bane. Anne Hathaway as Catwoman was ok, but nothing memorable. Marion Cotillard was miscast as Talia, and Robin was very poorly shoehorned in there. I did like some aspects of the plot, but not the characterisation of Bruce Wayne/Batman. There were some plotholes and stupid things in it. Overall, a poor way to end the trilogy.