Regardless of the GPS discrepancy, Cygnus completed its mission. How well did it do, and, does SpaceX now have a proper competitor?
Cygnus is an interesting choice as a competitor to Dragon.
There is something of an apples to oranges in the comparison.
Cygnus cannot return cargo.
Cygnus is using a booster (Antares) that uses engines built in the 1960/1970s (NK-33) of which there are a limited number left, and once they are gone, there is currently no way to produce more.
Cygnus and Antares have the feel of a thrown together design for just 11 flights, with little thought on what to do next. Some of this is outside Orbitals control, since the RD-180 they would like to use, ULA is blocking access to, legally. It appears to be for monopolistic purposes. (I.e. ULA uses the RD-180 from Russia to power the Atlas V, and do not wish there to be a competitor using the same engine).
Amusingly, the main body of Antares first stage is built by the same company that makes the Zenit booster, which also uses the RD-180, at which point, Orbital would basically be building a US Zenit booster, which is what Sea Launch/Land Launch is doing, with real Zenit boosters.
Dragon, by contrast, is just the first entry on a long roadmap of capabilities with a clear future. Dragon can reenter, and SpaceX has said they intend to reuse the capsule. The booster (Falcon 9) is working towards reusability, and the engines are made in house, so there is an active production line. (Claims of 400 engines a year have been made, but it is unclear if that includes Draco/SuperDraco engines in that count).
Dragon is planned to carry humans as a future option (2015?).
So for the very simplistic comparison of cargo only, upmass only, ignoring cost, Cygnus is a competitor. Cost wise, it is more expensive, it cannot return cargo, and no plans for manned flight.
So even in that model, not a good competitor. But in the crazy world of NASA, it is still potentially cheaper than other choices (SLS for example).