I would never thought this question would be asked in 2015.
My opinion of DVD (upscaled) vs Blu-ray quality is that it is dependant someone's personal taste.
Myself, if it ain't blu-ray or better it does not come into my house.
My wife, if a movie comes on vhs cassette she'll be fine with it (yuk).
If you are a videophile then blu-ray all the way.. If you are not then anything goes.