I don't own either, but I played with both this past weekend at Bass Pro Shops. I've always been a Minn Kota fan, and my observations of both units (actuation, noise level, space, looks, value) verified my original thoughts - Minn Kota Talon all the way.
It is VERY quiet, and they had one mounted on the back of a center console boat. With the boat on the trailer, when deployed, it would move the back of that boat / motor / trailer combo at least an inch or so up. POWERFUL stuff. It also has an alarm to let you know that it's still down if you try to drive off. Didn't see that working - just was told about it.
I'll own one soon. On the question of one or two units - that's going to depend on what you use it for. For my own purposes, I think one unit will do, but I only want it to keep me from moving away from the grass line I'm fishing when I'm fighting a fish. The wind tends to push me very far away from the grass line as I'm fighting a fish and retying afterwards. I want to get the fish out of the grass, but I don't want to end up 50 yards from the bank when I'm done.
If you want to be held perfectly still in one spot without swinging around at all - you're probably going to want two. For the very small increase in size - I'd only recommend the larger ones. They should be well worth the money.
All the best,
Glenn