They would still charge you the lease fee, but you'd own the equipment and could sell it at a decent price, and there'd be no commitment or early termination fee, as far as I know.
Comcast does allow monthly payments, but as i mentioned they seriously cut the price if you commit to an annual or two year deal. Last time I checked, they were offering digital cable, phone and internet for $99 a month if you made the two year commit.
You're sort of comparing apples to oranges if you're comparing an analog expanded basic cable bill vs a directv bill with HD, more channels, and a dvr. In my area Comcast would charge me about a $50 installation fee and around $88 a month for their digital preferred with HD and DVR after the promo pricing went away.
The directv similar package is n/c for the install and ~$75 a month after the promo.
Directv does get more expensive up front once you want more than one dvr or have more than 2 tv's, but the monthly fees where I live offset that after a year or two.
Of course, cable pricing varies rather wildly around the country, so YMMV.