Thrilla in Abila! ...or NetForum SchmetForum?
The NetForum Enterprise platform that has been in place at our organization for many years has been reliable, scale-able, relatively easy to interface, and very versatile. The main downside to the application environment is its difficulty in configuration that requires administrator involvement in the most minor of configuration changes. The market for support vendors is rather thin so major customization work gets pretty pricey.
In all, I would say that the platform has been acceptable enough to make it difficult to commit to replacing it. Customer service from Abila has been good and predictable. SErvice levels for hosting have been excellent.