I'm using them this year.
I've used the Magnus 2 blade "Nugent" blades for the past 4 years
I was unhappy with the way they always bend. Even on pass thru lung shots, the blade would bend just going into the ground. Hit a shoulder? Forget it, they bend around like the top of a Dairy Queen cone. I had that happen 2 seasons ago on what would've been the biggest buck of my life. I got a whole 1" of penetration and the arrow more or less just bounced off him.
Killed lots of deer with them but they are not very durable in my opinion.

I had some real bad luck several years ago with Spitfires and had given up on expandables til now.
I like the slide back design of the Tekan IIs over the flip over from the front that the Spitfires have.
We will see how they work.
I have 2 weeks before season starts.