Is poison master useful or valuable for a try in strategy ?
My main consideration when choosing Poison Master was, as Atomos rightly says, for the increased poison damage resistance it gave me as much as anything.
I'd paid a visit to the Poisoned River quest previously and had to admit defeat in areas I can now push through more easily with a lot less health loss, so less (or no) need to buy (so m)any HP/MP potions in the long run. That's always a good thing, whatever helps achieve it.
I'd bought the upgraded poison dagger when I joined the guild and picked up a poison bow along the way before I took the skill, so the additional damage immediately made them as viable as the magma shortsword/flaming dirk combo and enchanted Vulcan bow DPS-wise for enemies that were otherwise more flame-retardant and I just paired up the appropriate resists on armour for a given situation or area accordingly, as per usual.
As a rogue, taking an advantage to exploit an enemy weakness should be a given, if you can do so effectively.
Again, as Atomos indicates, there are more than occasional instances where both boosted poison offensive and defensive capabilities are very welcome indeed.
I'll admit though, I've never actually bought any poison yet but if I had one wish for a feature of the PM skill, it would be to let you use Tremadan's table (or any like it) to make your own from say x3 poison sacs for the spider venom and perhaps fangs or whatever for the stronger one. Maybe have the current poison sac quest unlock it, even..
"Of course, you'd need a Wizard's workbench but I don't know any that would let you spill venom all over theirs!"
For a feature that the game's never had; now that I've thought of it, I'm going to miss this one quite a lot!
If I was more familiar with the FLARE engine, I'd have a go at adding it myself, seriously!!
After my last comment on the composite bow though, I did try it out a bit more and found that the higher damage per hit saw me one-shotting stuff I'd previously been taking out with the old Hirge one-two, back of the head; so Hirge has been a bit bored with nothing to do despite her wearing my Girdle of the Rogue belt (and fancy hat that makes everybody like her when we go to the pub) so I do switch back to Jester's just to keep her cardio up.
I figure that if I do add poison to the bow too now, I'd likely one-shot enemies easier (as I might with Mass Crits) but I do so wish it was renewable in the manner I described above or something. I think I'd play to clear the whole map with that mechanic implemented.
I do still like the speed of Jester's for the reduced time to be able to move and thus dodge between shots fired if I do accidentally hit something off-screen that drags a mob in but being adequately prepared for close quarters to thin out the minions lets you dump a trap for a half-health boss by then and back up for target practice with a quiver full of reckoning, as long as you've got something that'll take big chunks out of their remaining health.
In some cases that's fire, in others it's poison; in many more still, having the option for both is twice as good.
Turns out, where you are now, I think those snakes have cold vulnerability and to the West, you'd need Death damage too but hit up the Weaponsmith in Friguld while you're there at least, as he's got a few nice pieces for a rogue.