One of my tablemates is playing one now.
Recommendations:
- Be a straight Beguiler, none of the prestige options we researched added anything to the class other than flavor, and the cloaked casting boni are worth keeping.
- Don't be a human. You don't need the feat or the extra skill points.
- Spell Focus in Enchantment over Illusion. You are primarily an enchanter.
- If you can swing the stat points and the DM hurdle, the feat that allows an Arcane caster limited access to a Domain spell list is much more powerful for a beguiler than for other arcane casters.
- Consider Heighten Spell, Repeat Spell, Twin Spell, and Imp Init. The standard metamagic feats don't do much of anything for you (Empower,Maximize, Quicken) and you are very much limited by your DC to have an effect in combat (There's no half damage effect on Enchantment spells).
- Have a plan for when the combat has monsters that you can't effect. Every PC in an Undead fight should be Blur'd, Displaced, Mage Armored, and Hasted.
- Invest in Escape Artist and magic items that grant movement. No D Door, Teleport, Fly means you have somewhat less mobility than other Arcane casters.
- Hesitate is your most powerful spell. Use it sparingly, and downplay its power to the DM.
Enjoy!