Lyon is a great city, but Bordeaux is a little smaller but there’s much more student environment, in the way that is more condensed. Bordeaux is student city while in Lyon you don’t feel that . Both are great though. read more
One comparison (Numbeo) lists Lyon as having a cost of living 1% higher than Bordeaux. Another comparison (Expatistan) estimates the overall cost of living in Lyon to be 1% cheaper than in Bordeaux. A 2013 report by the French media evaluated the cost of accomodation in Lyon at 4 800 euros / year, with Bordeaux standing at 4 830 euros / year. read more
That's 6 hours on the train, plus another hour or so getting into and out of town - eats up the better part of a day and leaves you very little time for sightseeing. besides, you can taste Bordeaux wines pretty much anywhere in France. read more