How is Sub/PvE on the PTR/Raid?

[RemJay24]

Always been a fan of Sub., and hoping it gets a few more buffs/perks once 5.4 releases to make it a better viable spec for PvE.

But much of its success relies heavily on the bosses in Siege.

I haven't had much time looking into the fights for 5.4 (mostly because I don't want to be super spoiled)... but am curious how Sub is performing against all the tested encounters thus far.

Are there a lot of fights where we can attack from behind with ease, or are there struggling times like Jin'Rokh (tank doesn't face him away from raid during pools), Mageara (during rampage), or other nuisances?

[Carp The Fish]

To put it as simply as possible:
It's better than it was this patch, but still not in as good a spot as Assassination and Combat. It can keep up regularly with the other 2 specs now, but it's still going to be limited by Backstab and the fact that the T16 4P is kind of ill-designed (it was to begin with, really).

To elaborate on T16 4P:
It was way too OP at first (an Ambush every 4 Backstabs turned the Subtlety game into "How close to 100% Find Weakness uptime can I get?" instead of maximizing what you're doing in Find Weakness. Currently, it's very RNG and underpowered because it acts like the old Arms mechanic where you'd have x% chance to get Colossus Smash back when you use certain movies.