of 5 players 3 are of the new classes: War Mage, Hexblade, and Scout. I played a Warlock one as well. I think they are very hit and miss having more flair then the core classes but not as much depth.
Conceptually, anyway, since I haven't had a chance to play them, I like the Scout, Swashbuckler, Hexblade, and the Warlock. Think Spellthief and Soulknife were better as PrCs. Have zero use for any of the oriental classes.
I like core classes best (including new ones); then short PrCs with few prerequisites (3-5 levels tops); and don't care for 10 level PrCs or those with lots of prerequisites much at all. This is mostly from a DM's point of view.
At the most in my campaign, I've had three of the new core classes used. A spellthief, the scout and a healer. Only the spellthief remains but he likes the class alot and is not considering a prestige class for a bit. I liked the new base classes, although I could have done without the ones released in the Miniatures Handbook
Dagnabbit! I forgot to include options for preferring PrCs over core classes and for preferring other groups of core classes to replace those from the PH (like Arcana Evolved).