Wouldn't willingly do w/out either, but one consideration that just MIGHT take it beyond mere preferences, is that a good new BH and subframe mount is gonna set you back $5500 or more whereas you can get a GREAT toothbar for $150 + or -.
Of course, since they do pretty much wholly different things, the question of which you can do w/out depends on what you are planning on doing.
You just can't dig deep narrow trenches, or any other small, deep holes with a FEL, either w/or w/out a toothbar. On the other hand, a BH isn't designed for, or particularly good at, carrying stuff.
Just a few hours of seat time has amply proven to me that the FEL, with a toothbar is a much better tool, for both digging and carrying, than one without (especially, with respect to carrying, when the toothbar is used in combination with bucket hooks and a length of chain).
....long as I could afford it budgetwise, I'd buy the BH, negotiate a modest price concession w/the dealer, and use that to buy a toothbar. /forums/images/graemlins/grin.gif