Are you most interested in the 400 or Comd?
If you want the 400 then Syd FO slots have gone to new hires in recent months. There are two reasons for this - firstly the EBA includes a lock-out clause which means you are locked on type for 18 months. Second, because the 400 has such limited routes in NSW, FOs don't necessarily want to be roped into SYD-CBR flying. That may change once new aircraft arrive late Aug and routes expand.
Time to Comd in Syd at the moment probably around 2 years. New comds haven't been awarded for short while as the fleet changes, but things will probably get moving soon with several Capts waiting their start dates elsewhere. Also remains to be seen how quickly they will push people through to Comd when they start getting down to FOs who don't hold an ATPL (a significant part of the roster these days, and growing).
Based on my knowledge of BNE seniority (reasonable), it appears that time to Comd is a bit longer, especially if you want to stay in BNE. I have no idea what their Capt attrition rate is going to be like in the next 6-12 months, so things might change. If they keep the CBR base open, you might get Comd very quickly by moving South. SSA don't have the 18 month lock in the EBA (no idea whether this will change?), but time to 400 in BNE is about 4-6 months after line check I would say? Again, much sooner if you want to move to CBR.
Having experienced culture in both SYD and BNE, there are definite pros and cons for each, but they all come down to personal preference and I'm not dumb enough to list them here. Either way you're working for one of the more professional regional airlines in the country, regardless of what the moaners and groaners might say.
That's as much as I got - good luck and stay out of that sun ...
Icarus