since this pressed format appeared,i noticed many ways it can be used the main difference in size and in sound quality i had some interesting experiments with simple but very useful soft called OggVorbis it remaking mp3 onto vorbis. you know i was confused a little, cause in mp3 song had 10 mb while in vorbis only 4... almost without losing quality,so since that time i thougt that this is the future format.now prevails mp3 of course, but situation may change within few years
Ogg Vorbis is superior to MP3s but MP3s has been around for so long it will be very hard to replace. Do note that many games like Unreal, doom3 and other big games use Ogg vorbis for their sounds.
i've noticed that by the way(about games),cause ogg format has a few chanels up to 5.-and it sounds great, so its also ideal for DvD video format. it can be replaced by wav for example but what about memory space?.. so we have next situation where ogg vorbis used 1.-games. as you've said 2.-in mobile phones. 3.-films there a lots other examples but herein a few mostly happend.
I have to agree with you that the sound quality and file size is better in OGG than MP3, but you can't use OGG in some MP3 players so that woudl be the major con for this.
Personally I prefer AAC files compared to both Vorbis and MP3. MP3 is outdated. Vorbis is much better compared to it.. but AAC is a bit better in terms of adoption... Vorbis is also CPU consuming... but in sound quality they are about par. And if you choose Vorbis choose VBR which is much better then MP3 with the same bit rate.