A GTP and ATB are no where close in comparison. A full size ATB or ETB is going to send you to the hospital. I personally saw a guy get nailed by a GTP in the palm. Upper tooth almost went threw and GTPs have short teeth (when looking at ETB). Carpets have the longest teeth in the Morelia genus.
If a ATB or GTP are your choices get an ATB because you're not ready for a chondro. No offense, just you need to do more homework before narrowing that down to the one you want. ATBs are hardy snakes (as are chondros) but require much less work.