The Sony MC-6 was designed almost exclusively for use with camcorders, meaning it probably has even worse embedded copy restrictions than the already-bad regular Sony recorders. At minimum, you likely need another recorder. The question then becomes how much do you want to spend? If you seriously think you'd be happy with straight-across dubs from the FiOS box, with no control over what the resulting DVD looks like or how it plays, then pretty much any cheap recorder will be serviceable. Look for closeout sales at jandr.com or other websites for the cheaper Magnavox or Toshiba models with no HDD: there are a few "tunerless" ones that go for well under $100. Or, if you have a decent PC, just record to the PC using whatever DVD-making software came bundled with it.
In fact, it might be best to try the PC a few times before investing in anything else. Most programs require you record to the HDD first, then make a high-speed burn to the DVD drive (burns take 10-15mins). Being forced to use the HDD means you'll be exposed to the advantages of the HDD: you can put chapter marks where you want (to easily jump over or delete commercials), select a custom thumbnail image for each recording, and quickly do all sorts of other customizations that make the DVD worth the effort of bothering in the first place. After doing this a few times you'll either agree this is very nice or decide you really don't give a crap and just want a permanent copy to file away for the hell of it that you'll probably never watch.
If its the latter, I honestly wouldn't even waste time making DVDs: get an extra HDD for your PC that you can dedicate to being your "media library", and just make dubs from your FiOS HDD to the PC HDD in DiVX, AVI or MP4 format (MP4s will transfer to an iPod/iPad). If you don't expect to lend or give these recordings to other people, storing everything on HDD is the easiest cheapest way to go nowadays. Cheap DVD recorders wear out quickly because recording directly to DVDs in real time is hell on their burners: cheap lasers have only a certain number of useful burning hours so at two hours per DVD it adds up fast.
A DVD/HDD recorder like the Magnavox 513 ($199) or 515 ($259) splits the difference between PCs and cheap recorders. You dub from FiOS HDD to the Magnavox HDD, which allows control, editing and customization. You then use the Magnavox burner to make a high speed burn to DVD. A high-speed burn at 15 mins is much more efficient and accurate than a real-time direct-to-dvd burn from FiOS, and less stressful to the burner laser. If you think you'll be making a large number of FiOS backups, the most sensible choice is either PC file storage or a Magnavox DVD recorder with HDD. Recorders without HDD, like the MC-6, just don't work that well for this unless you spend for the expensive Panasonic EA-18, EZ-28 or EA-38 models (which cost as much or more than the Magnavox 513 anyway).