Assuming that the instrument has no leaks and is produced by a known manufacturer, the problems described in this thread are overcome by using a good reed and PRACTICING. Fifteen minutes per day doesn't cut it.So over the my school winter break, I've been putting in some time on the ole' oboe and flute. Flute is a regular double and I haven't put in serious practice in many years. Oboe is still 'up and coming.' After I decided to work with soft-ish reeds and quit trying to fight the reed, I've made real progress.
Sax, Flute, and Clarinet seem to make logical sense in terms of keys. Oboe seems to be intentionally designed to be difficult to play. The Eb and c pinky and F/F# are flipped and a double octave key. Saxophones lost that in the late 1800's. About ? of the keys have a purpose but I have yet to need them.
The last a most interesting item is that the more you spend on an oboe the easier they are to play. Automatic Octave Key, Third Octave Key, Left Hand F, all the trill keys, no pinky needed for Forked F, and a Low Bb. Imagine giving a beginner sax player a double octave key saxophone without bell keys and charging $2,000.