I use Fencer quite often on WAR with Kirins's sword and Blurred +1 Shield, Fencer Savage or Cloud Splitter is stupid powerful. The crit effect is very noticable and it does work on Vorpal though you won't often use a crit WS while also using Fencer because it favors high fTP single hit WS's.
This, though I've hit some stupid Vorpal Blade numbers with blood rage up. If you choose to dual wield on Warrior, Vorpal Blade spam is pretty strong as well, as is Savage Blade if you end up having an over flow of tp. I'd only use it for screwing around/ambuscade. Tanmo+1/Sangarius+1 is a pretty nice combination.
Weaponskill damage is a bit less, but the weaponskill frequency is greater than sword shield (that is a given though).
With fencer it (Vorpal Blade) only seems worth using when Sekkanoki is up.
Calamity is pretty powerful as well with fencer, but the skillchain properties are crap.
Mistral Axe can also give you a nice ranged option.
IMO Fencer's main strength is being able to mitigate damage/tank while being able to weaponskill for high numbers.