For one, OGG is open. Also, OGG is smaller. Third, OGG Vorbis uses superior compression algorithms than MP3. Last but not least, it loops perfectly. It's just a better format overal.
While MP3 and OGG are comparable, Construct actually wants you to use WAV files here and there. The best you can do in that case is using Microsoft's ADPCM codec, which is absolutely horrendous and unacceptable by today's standards.
It also just confuses me that there is such limited and sometimes broken support for OGG in Construct, while proprietary formats like MP3 are supported.
Maybe it sounds like I'm complaining, but I'm really just being a critic. I really love Construct
But even though I love it, it is important to remain a critic ;D All the time