Hi Harley,
The 4 great wrecks are in Labuan ( was part of Brunei, not anymore ) can be easily reached from Brunei. We used Scubatech Int. at Empire hotel - they operate high speed catamaran, approx. 1 hour to the site. It is more convenient to dive Labuan from Brunei rather than from Labuan. Other sites in Brunei such as ampa patch, champion reef, abandoned platform, ect. are nice although the sea can bit chopy and viz not excelent.
Diving at live platform is no longer allowed for safety reason.
The Brunei people are very nice and friendly - we really enjoy our time here, good place for family - may be nothing for bachelor & practically no night life, no bar, no karaoke, no alcohol in the public places. If you can survive without these, you may love it.
As most people here using their own car - public transportation is not very easy.