Cons: A Beguiler, like a rogue, is very vulnerable to certain types of enemies unless they can cover their gaps with specialized magical items. Mindless creatures, those immune to Enchantments or Illusions, creatures with blindsight, true seeing, high SR, or even a high will save can be tough for Beguilers to beat.

Illusions and Enchantments derive much of their power from the creativity of the player and the cooperation of the DM. A player who just wants to blast his enemies will not do well with a beguiler. A DM whose NPC's always attempt to subvert commands and who are all paranoid of illusions can cripple a Beguiler.

While the Beguiler knows more spells than a sorcerer, and is absolutely better than a Sorcerer who takes only Enchantment and Illusion spells, it lacks the versatility of Sorcerers or Wizards to have the right tool on hand for every situation.

While superior in mundane combat to low level sorcerers and wizards, the beguiler is still one of the weakest combatants in the game, and the Surprise Casting class feature is almost a trap to lure unsuspecting players near their enemies where they can be crushed. -Braithwaite

Pros: Beguiler is probably the most flexible of the three "specialist Sorcerers", the other two being Dread Necromancer and Warmage.

For an arcane caster, the beguiler is reasonably hardy. Light armor is roughly equal to a sorcerer's Mage Armor, without taking up a spell slot. Weapon proficiencies similar to a rogue and d6 hit points per level mean that at low level the Beguiler can be marginally better in combat than a wizard.

The beguiler is a top of the line skill monkey. They really have more than 6 skill points per level, because Int is their casting stat, and they are almost obliged to keep it as high as possible anyway. They have trapfinding. If they decide to ignore parts of their excellent skill list, they can cover the gaps with their flexible spell list. For example, a beguiler with low hide can replace it with invisibility or silent image, or a beguiler with bad social skills can recover with charms, Suggestion, or Dominate. Use Magic Device can be used to mask some of their weaknesses.

The beguiler is a full caster. They automatically know every spell on their spell list, and their spell list can be widened by a number of feats, prestige classes, and the advanced learning class feature. At each spell level their list includes a number of excellent spells. They get some free metamagic feats and their cloaked casting ability helps them overcome enemy defenses when casting on opponents who are denied their dex bonuses.

The beguiler is capable of doing one thing quite well. It is excellent at neutralizing opponents with charms and illusions. When that is inappropriate, it can still contribute with Trapfinding, Use Magic Device, or a handful of buff spells. -Braithwaite