I've never used the TL, and have only looked on their web site. Have never seen one in person.

I have used a Summit Viper.

The thing that comes to mind is that the Summit (as well as almost all "conventional" climbers) allow you to hunt standing and have a 360 degree view. WIth the viper, you can easily move the seat as well as the foot loops out of the way and basically have a clear 360 degree platform to stand on.

With the seat down, back rest in place, and the optional fold out foot rest in place, my guess is that the seated position is as comfortable as the TL. It's awfully durn comfortable and nap-able

Just a thought - consider the stand up position each offers. It's important as overall sitting comfort, imho.