It may be the most "commonly prescribed" but it's not the best. The best(in BG's opinion) is Fortaz. Most Vets have no clue what it is though. If they do, there's a good chance you're at a good reptile Vet. If they've never heard of it....find another...REALLY.
It is much better to give both Fortaz and Baytril than just one or the other. This will cure 90% of anything your snake may get. A lot of Vets that know what they're doing will prescibe this treatment while waiting on a culture....or they may just prescribe it to see if it works. If it doesn't, then a culture is needed for sure.
It all depends. It can be prescribed a few different ways with varying success.