I dislike the 90, but I'll take it if it is coming. The 90 (and the 92 & 93) buses I encounter tend to be old or crowded or dirty or a combination of the three. The 96, is a bit better, it also has a different route and where it turns off on to New Jersey, as the other 90s continue along Florida. The 96 then goes by Union Station, and then the Library of Congress, where it goes after that, I don't think about.
It also goes by the Supreme Court. That's what I thought of when I read that Supreme Court justice Sonia Sotomayor bought a condo in the U Street area. If the condo is really close to U St NW she could, if she so desired, take the 96 bus that would dump her off right at work. I've stood many a time outside the Supreme Court, after leaving the Library of Congress, waiting for the 96 to get back home.
If she uses a smartphone app like NextBus DC, she can figure out how long it takes her to get to the bus stop from her condo (giving a 3-5 minute buffer in case the driver is a yellow-now red light running speed demon) to the bus stop and get to work in about 27 minutes. The metro may be a bit faster but there is that whole having to transfer at L'Enfant, thing.