It more depends on features you already implemented. Check the arxiv file, if you do not have all those features already (lookahead lm, proper sentencepiece, label smoothing), consider this espresso.
I think the question was more on what framework should be preferred to tensorflow now?
Or at least that's my question - as someone who has taken an interest in this area since the deepdream days, but is only now considering diving in fully, what platforms should I be looking at, if not tensorflow?
I'm working on a speech model in tensorflow. What should I be using?