I've only thrown a Katana once or twice and I don't believe that the Tern is as understable as the Katana. (I have two Champion Terns around 165g.)
I just got two backups for my Wahoo that I love last weekend. I took my three Wahoos, two Terns and a Frenzy that I have out to the practice field tonight. I got the Terns and Frenzy hoping that they would fly like the Wahoo for me, but in more durable plastic. Then I thought that I'd still just get a couple more Wahoos.
Anyway... The Wahoos are a little more understable than the Terns, but fly very similarly for me. As long as I throw them properly, RHBH, the Wahoos turn right a little bit more than the Terns, but not a lot. The Wahoos are a little easier to turn over and will crash and burn if I mess up my form. Today, I was just trying to throw them with a level release and not too high. I have to hyzer my broken in Wahoo a little. I was throwing the Terns around 350' and the Wahoos just a little futher, maxing out at 370'.
I was pretty pleased with these results as my primary drivers, QOLFs, typically max out at 325' for me.
As far as the Frenzy goes, anyone interested in buying or trading for one? It just didn't feel the same in my hand and, for me, actually flew overstable with no turn at all. This isn't what I was looking for.