One company seeking the Fairfax County cable television franchise promises 95 channels, two-way communications for banking and shopping and millions of dollars for locally produced programs.

The other company seeking the valuable cable monopoly promises 107 channels, two-way communications and millions of dollars for local programming.

In other words, it may not matter much to the typical Fairfax County television viewer which company wins the franchise sometime next month. Both Fairfax Telecommunications Co. and Media General Cable of Fairfax Co. Inc. are promising similar technological marvels for the county's 600,000 residents, as well as the sports and movie channels that most cable consumers say they want.

Each company tried to dazzle the County Board of Supervisors last week with slide shows and movies, bolstered by some ferocious lobbying, all designed to prove the superiority of its offering. But the supervisors have focused less on the firms' promises than on their ability to keep those promises--on schedule and at their quoted prices.

"We don't want this thing to fall flat," said Supervisor Thomas M. Davis III, expressing the fear that has motivated the board during three years of preparation. "We don't want them coming in for rate increases, and we don't want the company to bail out."

Fletcher Cox, a writer for Fairfax Telecommunications, said it differently at the board's public hearing Friday night: "I think in the end it will come down to who you trust."

Whichever firm the county board trusts, some Fairfax residents should have cable within a year of the franchise award, and the entire system must be built within five years, according to the county's plan. Having watched local cable companies sell out in Alexandria and fall short of promised performance in Arlington, however, the Fairfax supervisors have ordered their staff and consultant to scrutinize the two applicants' ability to build the $100 million county-wide system without delay and without raising rates.

Neither firm, the consultant suggested, has proposed realistic rates. Fairfax Telecommunications may have overestimated how much its revenues will be, and Media General may have underestimated its costs, the consultant said.

Fairfax Telecommunications has promised to serve the entire county within five years, including the households in Fairfax's sparsely developed western and southern sections. Media General has promised to serve 94 percent of the households, with 5 percent more getting service if they pay about $100 extra at the start.

Although Fairfax Telecommunications has used its coverage as a selling point, some supervisors said its plan would increase rates for some subscribers who would have to subsidize the costs of its service to rural areas. "Media General is based on a more equitable plan of people paying the cost where the cost is borne," said Board Chairman John F. Herrity.

Overall, Media General has offered better programming at a lower cost, according to the county staff and the consultant. Subscribers could pay $2.95 a month for 63 channels, including the Washington and Baltimore stations, local access programs, Cable News Network 1 and access to two entertainment channels, the Disney Channel and Front Row, for $7.95 more for each.

The total cost for 76 channels, including the sports network, ESPN, and two pay services, like Home Box Office, would be $24.85 per month. For 96 channels, three pay services and a program guide, a Media General subscriber would pay $36.75.

At the basic level, Fairfax Telecommunications would be more expensive than Media General. For $6.25 a month, subscribers would receive 57 channels, mostly Baltimore and Washington stations along with local access programming and access to movie channels for $6.95 each.

For 67 channels and two pay services, however, subscribers would pay $25.40, only a little more than for a comparable package with Media General. At the higher end, Fairfax Telecommunications again becomes more expensive, charging $41.25 a month for 81 channels, three pay services and a program guide.

Both firms may raise their prices after four years, however, and so the evaluation teams studied their performance in other jurisdictions. Unfortunately, the teams found Richmond-based Media General owns several daily newspapers but only one cable system, located in and around Fredericksburg, Va. Denver-based Telecommunications has experience mostly in buying small, existing systems--what its president called "taking over problem children and making them viable performers."

As a result, the supervisors' decision may be in part political--based on a desire not to offend Fairfax Telecommunications' local shareholders, or on a desire to appear resistant to their pressure--and in part intuitive, based on their feel for which company is more likely to perform. One supervisor, Davis, has suggested splitting the county in half and making each company a winner.

In any event there is little question that the board will award the franchise next month, probably at its July 19 meeting. The public pressure for cable has been mounting, said Davis, ever since newspapers and TV Guide began publishing cable movie listings.