I certainly won't begrudge anyone for regrading Bradman as the best.
But personally I don't consider him solely on the fact that the game he played a cricket so different it was almost a different sport. It's like the 'open era' in tennis that includes players of a certain time who are considered because that was the sport as it became known.
As far as I know,
Bradman played against one country and in two countires as compared to traveling all around the world playing against 8 test nations on a whole host of ALIEN environments and pitches. Bradman basically played in his backyard all the time.
Bradman played such few tests each year as compared to in addition to all that travellning the schedule that exists today where you play so much cricket it's ridiculous. 40 one dayers a year, lots of tests, tours, T20's, IPL, World Cups, Champions Trophies, Champions League's.
Bradman played in an era where the media was nothing like it is today. The demands and pressures today, especially in Pakistan and India, on players to perform is madness. It's like the English national team. A sport is very different when you have that sort of pressure on you.
All in all, as I said I won't criticize anyone for considering him the best. But for me cricket changed a great deal since then and I can't consider someone whose played a sport so different from the one we know today. Which doesn't mean you disregard all the great players before today, but I think Bradman's cricket was one step too far. It just cannot be compared to the one today, even as a sport, forget its players. In my humble opinion of course.