Got mine today too, I have to say the two spellcasters gave me a double take.
The Beguiler is a Thief/ Sorcerer and the Duskblade is a Fighter/ Sorcerer.
The Beguiler knows all spells on his spell list at every level he has access to and can cast a number of spells per day like a Sorcerer. And while his spell list is rather limited he does get several free feats; Armored casting, silent spell, still spell, spell penetration and spell focus.
The Duskblade has a much more limited number of spells known, basically he gets one every level but makes up for it with 4 first level spells as a spell-like ability and several bonus feats; armored casting, combat casting, quicken spell and spell penetration. He has access to spells up to 5th level but at 20th level, he can cast 6 zero, 10 first, 10 second, 10 third, 8 fourth and 6 fifth level spells per day.
Maybe it is just me, but aside from their limited spell list, they seem to be better spellcasters than a true Wizard or Sorcerer. When you add in their Thief and Fighter abilities they may outshine the true Wizards and Sorcerers.