I played a bit with the BN stock ROM and then directly installed CM11 following these instructions here:
http://forum.xda-developers.com/show...26&postcount=7
Everything worked very well. The only problem was that I could not mark the partition on the uSD card as active through the disk manager on windows 7, but using diskpart on the command line worked (description here
http://technet.microsoft.com/en-us/l...=ws.10%29.aspx)
One thing I noticed is that for large pdfs (50 MB) all of the readers that I've tried (acroread, moon+, MuPDF) are not very responsive. Sometimes it takes 2 seconds to flip a page. Unfortunately I didn't try this on the BN ROM, so I don't know if it would be different. I highly doubt it.
In general I am very happy with CM.
Thanks everyone for your comments.