Both are amazing. End of. Lee is the definitive Dracula, while Cushing is the definitive Baron Frankenstein and Professor Van Helsing. The other films they did together outside of Hammer are a lot of fun too, such as the Amicus anthologies, The Creeping Flesh, I Monster and Horror Express.
Speaking of Fu Manchu, I ordered The Face of Fu Manchu and The Vengeance of Fu Manchu from Townsend Records and they still haven't arrived
! I got The Brides of Fu Manchu no problem from Buy It Here. The DVDs were quite cheap considering they are going for like £50 on Amazon Marketplace.