Actually, it's been quite a while since we had a "cello on or cello off" question around here ... used to be, that was the first question every new guy asked but that seems to have changed ... and in some ways, addressing a question that has been asked and answered hundreds (or more) times somehow seems less tedious and tiresome than reading yet another GWB-bashing post ...
IMO, on or off, it doesn't really matter ... they'll age equally well either way ... half the guys here will argue with you whichever way you go, but "on" does have the virtue of protecting the wrapper from damage from handling or brushing against other cigars, etc. that can occur over time .... but if you do go the cello on route, to the extent that you can do so, try to keep the "ons" seperate from those that came without, because those without WILL get rather dinged up by the cello on their neighbors ...
Finally, if you choose the "on" method, one thing that pretty much all of us will advise you to do is remove the cello before lighting your cigar (although you may find you like the colorful "flare" lighting the cello produces ...