Since the time I opened this thread, I have in fact seen a dramatic improvement in performance on my Mac - so possibly my issue was due to the extended background indexing issue. I'm very relieved! Will post again if I see further performance issues, and I agree that it would be good to somehow set user expectations with a prompt when the update occurs.
My Evernote app was just updated and now it takes almost two minutes just for a note to show up after I select it on the lefts-side note list. That makes my envernote on MAC pretty much un-usable. Any advice on how to improve the slowness? I have a MAC Mini i5 processor, premium evernote account and a moderate sized database - been using evernote for around 3 years now. Evernote app just updated to 6.0.3 and it told me it was "migrating the database" which took a while.