Mirror matches are the main reason I would include Steal Equipment in my Forcemaster books. Stealing their Galvitar is pretty funny. All they have to do is then Dissolve it to get it back, assuming they don't have a Steal Equipment spell themselves, so it's not really an "I win" button, but it's still funny.
Forcefield shouldn't ever cause a standstill between Forcemasters though. With no other creatures, they can still use Galvitar to double strike each round and cause damage. Assuming that for some reason you don't want to simply Dispel their Forcefield.
I think all of the mages make for interesting mirror matches though. I'm not sure if I'd say any of them stacked up well or poorly against themselves though. You can't really get more balanced or evenly matched than facing yourself can you?
If I had to say someone stacked up poorly against himself though, I'd have to say a Necromancer. When you're facing off against a bunch of Bloodthirsty Zombies and you know your mage is the only living creature you will be bringing to bear, it makes you sweat a little.
