Also known as nightmares for even remotely serious players. For a Cleric/FvS, they are an abomination.
Even my Paladin has troubles, since she has healing, often times I have to become the main healer in a party that already includes a Cleric! Either the cleric will not support the group, or the Cleric is overrun by the rest of the party scattering and getting killed. When in doubt, stick by your Cleric.
Rogues can be alot easier than Arcane casters (Divine casters are no challenge to solo, really. They can heal most damage and effects easily, and grant themselves immunity to traps once they get level 3 spells). You just have to build them with an eye towards doing solid damage in melee.
Thus mine totes two Dwarven Axes (1d10base + 1enchant +1Dwarf Enhancement + 3STR mod = 6-16 damage per hit, ignoring any damage boosting things like Frost or Flaming; or Backstabbing for that matter). With Backstabbing, I get 1d6 additional damage on top of that (7-22) and if I have a Frost/Flame etc weapon I get a 1d6 on top of that (8-28).
Since Rogues use the skill system of DnD, and not a lot of feats are really required, you have feats to burn towards building their damage potential. Past that, it's getting UMD up enough to self-heal with wands and scrolls. Mine just has enough to use a CLW wand semi-reliably. At level 3 (with 1 level of Fighter no less).