Totally, I’m just sad a transcode is still needed on the Android platform, even when users have been nagging about it for some time. There’s this rather lengthy thread, for example. Nvidia SHIELD/Android app SSA/ASS format anime subtitles + transcoding problems
I’m not really knowlegdeable about the code of Kodi vs Plex, but from my experience it seems like Kodi somehow makes sure that everything progresses, even though it means “skipping” a bit.
From the end user perspective it seems like Plex will just slow down untill it either crashes or are somehow able to catch up, the video freezes and so on until the subtitle animation is over. While Kodi seem to “skip ahead” in the video at certain points, I think it’s like twice a second, to make sure it doesn’t lag too much behind the actual time in the video. I don’t know if that made sense. It’s probably not related directly to libass performance, but they seem to have figured out some clever way of making sure playback doesn’t slow down too much, even in the case of excessively animated subs.
It’s a very extreme case though. I rarely experience these kinds of ridiculus sub animations these days, but they do happen from time to time with anime. 
I’m usually using PMP on my HTPC, so that’s what I’m usually comparing with. 
