I've never kept them but they have been at the top of my favorite list for a long time. I've read plenty about them and have met (in person) a couple of people that keep them.
I personally prefer the Emerald Tree Boas, but the Gree Tree Pythons stay a bit smaller. The GTPs also do not have the fangs the ETBs do. Both have very similar requirements and very similar behavior, depsite from being from different ends of the Earth.
They require a higher temperature range than most other Pythons (or Boas) and also require a higher humidity. When I say 'require' I do mean 'require'. They will not thrive without the high humidity. Many keepers use misting systems to keep the enclosure properly moist. A decent sized water dish with a powerhead and a heater will also be able to serve this function.
They are typically a "display animal" as they are known to be quite nippy, even as adults. They are generally nocturnal which makes them 'lazier' during the day which can be utilized in handling. But at night the preditor in them awakes and it's rare to be able to handle them in later hours.
If you consider the larger growing Emerald Tree Boas, be sure to read up on their fangs. They get very large for a constrictor.