Which of these reels would you pair with a 6'6" heavy fast action rod for throwing large blades in the 1/2 - 1 oz range and why? Any better suggestions in a similar price range?

That's the new STX with dual breaking.

Supposedly the Zillion handles heavier baits very well, so my initial reaction would be to go with that, but I have also heard only good things about the STX. I can't be too much of help because I have only used my friend's Zillion a couple of times, but it definitely excels with heavier lures.

Zillion...its not even close.

The zillion

By a large margin

It's not as far away as people as some are suggesting.  Go to the TackleTour review between the Zillion, Quantum, Revo SX and the Shimano something or other.

The SX came in a close #2 after the Zillion.  That's the old SX against the Zillion.  Beside what the old STX had over the old SX, the new STX has upgraded braking and superior drag performance.

I've fished them side by side you really can't go wrong with either of those two reels.

It's not as far away as people as some are suggesting. Go to the TackleTour review between the Zillion, Quantum, Revo SX and the Shimano something or other.

The SX came in a close #2 after the Zillion. That's the old SX against the Zillion. Beside what the old STX had over the old SX, the new STX has upgraded braking and superior drag performance.

I've fished them side by side you really can't go wrong with either of those two reels.

Now that the braking has changed, I'm gonna give the new STX another go.  The old STX was all suck....

Which of these reels would you pair with a 6'6" heavy fast action rod for throwing large blades in the 1/2 - 1 oz range and why? Any better suggestions in a similar price range?

500% ZILLION! It's a bulletproof reel!

zillion. both are nice. i like the zillion better, and i think it will last longer. i've had several zillions for as long as they have been around, and have yet to have an issue with any of them.

I agree with Pantera. Not as much difference as some are suggesting. 

The Zillion is a little more refined, but it costs a little more. As far as performance, they are very, very close. The STX has a better drag, though.  Want looks, go Zillion. Want price, go STX. Either way, you get a good reel.