I agreed with everything up until this:
Vorbis and Theora are comparable to their best closed counterparts. VP8/WebM has totally closed the gap with H.264, for those who like to split hairs about Theora.
Vorbis is awesome. It's on par with the best AAC encoders, and better than the average ones.
Ogg as a container is quite lackluster - it's not really suitable for video; tons of people have seek lag with it, which other containers like mkv don't have.
Theora is laughable compared to H.264, but it is decent compared to MPEG2.
VP8 is rather close to H.264 Baseline, but for PC-streaming, you should be enabling all the advanced stuff in the High profile. x264 tweaked properly can halve the bitrate over again, with no perceived quality loss.