Hoysepis stomped me completely. He would fly in with semi-preps - likely aura/shield, which you can keep up almost all the time, and smash me a few times with silverback gorilla form. If I were prepped and ready, STSF would charge up in ~10+ rounds and he would leave and not re-engage for the next half a day or a day.
If I weren't ready, he'd outdamage me easily and I would be forced to flee. I don't have enough preps to constantly be prepped against an air form dropping on me, so he beat me around pretty badly. I would head straight for the Underdark every time he started jumping on me, because I wasn't about to kill him if I were prepped.
So air/off catching STSF unprepped = air/off wins.
Same principle goes for overwhelming offence - big damage warriors would easily destroy me if I were unprepped. For example, Aoirse would easily beat me with polearm/critical if I'm not prepped. However because of mobility, I had the advantage, since I could chase if I got the upper hand, and flee if I didn't. Raeth also did well because a single ambush on an unprepped foe would deal ~500 hp damage, and each serpentstrike would take ~150. STSF isn't reliable for evading direct damage (I very, very seldom saw it fire), nor are evade/parry anything, contrary to popular belief.
Malediction builds (Magner) would beat me if I didn't have absolutely top-end gear. Most STSF sword warriors are not going to have that. Liantae is probably played by an exceptionally strong player, so that is an outlier. I would estimate myself on the higher end of players as well, so Altariel would also be an outlier.
Caster types:
I didn't have problems with shamans. ~50 svs, whips, lash, and offhand would make it a generally bad idea for most shamans to attempt fighting me. I imagine the same goes for Liantae (pincer) and Xeneth (crushingblow). Druids were also quite easy with non-metal whip/flail.
Transmuters might have a good shot, depending on my svs/svpar. Never had to fight one though. Competent conjurer would destroy me - Twilbo did, when his archangel was happy with spells. Same would go for devil conjurer or challegha conjurer. Dispel the resist/stoneskin/protection and go to town.
Necro would have a hard time since the army cannot get past swords, and only crimson/poison/pwdecay check CON instead of svs. Surprisingly few necros used that on low-con STSF warriors. Instead I keep seeing necros use power word kill or weaken or something - Khalmarnasa I'm looking at you :-)
I didn't fight invokers, but a good invoker would easily destroy me with just A/S - needs rain of stone and shield of slime. Fortunately I never had to fight a competent invoker with rain/quicksand/slime. If I played Volker (Scion invoker) against Altariel, Altariel wouldn't have a chance outside of a shameless gank - and even then, if the gankers triggered shield of electricity Volker might just end up beating them all up between rain/elec/pillar. Volker was easily my most overpowered character though.
High damage paladins would beat me.
The trick with building a good STSF sword spec is your second spec. The second spec needs to be excellent at offence and also lag well - Liantae had axe, Altariel had whip. This way you can destroy the people who counter your sword spec (non-melee caster/communer types) with overwhelming offence.
STSF elf is a very strong build, and quite fun to play. You should try it some time. I recommend dark-elf STSF sword/axe Imperial. Maybe take Riddle.