I like the spring loaded WBT spades a great deal, rock solid lock even with hard metal terminals.
If you go with a solid, low tech spade, make sure you get a big enough crimp tool to create the right amount of pressure.
I have used the Furez spades for a situation where I was co-joining a bi-wire set of two huge gauge speaker wires with a single spade at the amp end. I like that they are solid copper and seem well-built.
I also like Furutech's FP-201 (R or G). Their FT-211 or CF-201 may work but I have not used them.