One of the things I'll miss is the "upgrade a registered O'Reilly print book to an ebook for $4.99" option. Always nice to have both the print and [affordable] ebook versions. Bummer.
That and their daily half-off sales have resulted in me spending far too much money on their books... At least they generally have good editing and a pretty high quality bar, better than I've seen with Packt or Apress.
Glad to hear you've enjoyed our stuff. We really do try to do a good job with it! :)