Hey Ainulindale,
since im only playing on Insomnia I am able to give you some informations about this server.
First of all Insomnia is a Chapter II based server with some modifications like class balancing, instance adjustments (long and exciting boss fights) and bugfixes.
Max LvL is 55 and all instances up to Hall of Survivors are open.
As the diamond prices in the AH are very low(3-4k/each) its easy for beginners to start playing here.
Exp, Tp and Drop rates here are not modified, still sometimes there are some double exp/drop rate events.
We also have active GMs, and a pretty fast replying support.
If you have any additional question feel free to PM me.
Izii