Of coarse I have, I'm the Official Bioware Forum Monkey. As well as the Official NWN Chat Lawn Gnome.
However, you're persistent world set is unique to Avlis (thus far) and (from what we the public know) has only been tested in one environment on one machine. I am assuming you've probably extending testing to your friends, but that is still not such a great scale.
It is easy to claim you've done it before BioWare, as it is true (BioWare isn't due til march), however "better" cannot be assured. BioWare's methods will be internal requiring to child processes, which may (or may not) affect the efficiency of the system.
Bioware also has (obviously) direct access to the game's source code, which can allow for in-game optimization that your current SQL-based system cannot offer (again, from what information you've recieved.)
The fact that the source code for your project will also not be released disturbs many people, and it's already a commonchat joke that we're going to wake up one morning and see a CERT warning for NWX.

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I'm not implying you would trojan the users, or use any other method to obtain any information, but I am stating that not releasing the source hurts your project.
I am happy to see that you all have the skill required to work out such a system, but in March, BioWare will release an official one that may (or again, may not) be better, if in the former case, your system will effectively be useless, unless it offers manipulation BioWare's ingame system cannot provide (which is doubtful, as, again, BioWare has direct access to the game's source). However, if in such case that BioWare screws up, then I believe everyone will be happy to have Avlis's NWX system.
In the meanwhile, I'm going to go work on my NWRPX scripts..