Fellow Blu-ray owner here and since you are asking about Blu-ray specific, here's my take:
Netflix has been very good and we have been much happier with them than our old experience with Blockbuster years ago.
However - Netflix has now signed deals with Warner and another studio so that new releases will not be available AT ALL for the four weeks after release. You also pay more money for the Netflix Bluray plan (an extra $2 per month) whereas BB does not charge you extra. If you compare the 3 discs at a time unlimited plans between the two BB is the cheaper option and does not have the four week delay on new releases.
However again - many bluray users that have BB complain that even though BB does not have the delay they have such low inventories of blurays that they often have to wait forever anyway and they are constantly getting discs way down their queue instead of their higher listed discs.
I cannot comment on the BB streaming as we have never tried it - our LG bluray has Netflix built in but we have used it and enjoy it a lot.
And in case you have no already, go right away to
www.blu-ray.com and join the forums. It is the DIS of Bluray. Especially helpful is the Hot Deals forum where everyone posts sales, price drops, etc. They also have a price tracker for every bluray available that tracks the historic price on
Amazon and you can set a target price and if a title drops to your range it will email you. Mucho cool.
Beware, however. Spending too much time in the deals forum can be hazardous to your wallet because you will wind up buying disc after disc because the deals are too good to pass up, lol.