I personally mix 2 Celestion G12K-100s with 2 EVM-12L black labels. That cab I then also combine with a 2 x 15, 2 x 8 cab. The G12K-100 matches really nicely with the EVM-12L black label, in my experience. I love the grind of the G12K, especially the low end handling, and the EVM just takes everything you throw at it. I'd say the EVM is a more neutral speaker than the G12K, but they complement each other nicely. Oh, and the power handling is just incredible (300W for these puppies - EACH!). Cracking :)
Roo