No experience but a handful of my Gonyosoma contacts also keep Philodryas spp. Without exception everyone raves about them and encourage me to keep them. No denying their beauty, that's for sure.
-----
Current snakes:

0.0.1 Gonyosoma oxycephala - Java locale (green)

1.2 Gonyosoma oxycephala - Jave local (green)

2.2 Gonyosoma janseni - Seleyar locale (all black)

1.2 Gonyosoma janseni - Celebes locale (Black & Tan)