MP3 in my experiences sounds worse compared to ogg. There are however many profile settings comes for both codecs, which settings are not exposed to the engine as youcan see. You can either find ways to modify the codec behavior and turn it to your requirements (eg, change the stereo mixdown to avoid the use of m/s joint-stereo?) , or you can move to more ‘expensive’ solutions such as wwise/fmod to get some different results.
Yes, and it’s a very efficient codec algorithm to playback compressed audio in realtime. It allows the playback of dozens (if hundred) of samples concurrently, which is the point. You can’t really expect pristine quality when a solution is optimised for high scalability and low performance consuptions in mind.
That being said, i think with enough experiments you can get to the point where the audio sounds good enough for you. You should also look into the engine’s built in media framework which supports high range of sources for audio and video both.
The 22k / 44k limitation is absolutely false, the engie can in fact play many sample rates, and to my experiences 48k suits the best to the new audio modules.
Btw, you sure you have setup the engine to use the new (experimental) audio mixer feature? That could potentially ‘sound’ better.