Firefly DVD commentaries?

So, N. and I have watched all 15 episodes of Firefly, on DVD, in the right order,
as JW wanted us to see them. And we've watched the special features.

Whew...what a series.

Which episodes are worth re-watching with the commentary track running?

Please let me know if they are all worth seeing, and/or if there were particular
stand-outs that you'd recommend.

Thanks!

-B