The bass player across the street (much more experienced than me) told me that two 10 inches will sound better cause you'll get better top end, does that sound right? But I guess that might jack up the price a bit? Could be relevant, if the OP cares.
Whether or not a 210 sounds "better", depends on what kind of sound the player is looking for, and the basic construction of the particular cabinet in question. Maybe to him a 210 sounds better, but it may not be what you are looking for. It's all a matter of personal preference, no one speaker configuration is inherently better than another.