Basically, when comparing roughly equivalent packages, the Baucus package imposes significantly higher premiums than the Massachusetts package. If the Baucus bill had subsidies as generous as the House bill, the gap would close, although not disappear.
Keep in mind, though, that this chart only looks at the middle class. As Beaudrot notes, the protection for families making less than $31,000--that is, less than 133 percent of the poverty line, is much better. That's because these people end up on Medicaid. (Right now, only some segments of that population do.) That's a huge improvement for a huge number of people, and not something to be taken lightly when evaluating the merits of what Baucus has put forward.