I use all of them in Brisbane ... Downunder camping, Tentworld, BCF, Anaconda.
Typically downunder and tentworld have the lowest "usual" price but often BCF and Anaconda have specials which make them comparable and occasionally cheaper.
I bought an expensive tent and fridge at tentworld recently and they were the cheapest I could find ... but they wouldn't budge on price much because they knew they were already the cheapest even though the total purchase was around $3k. Of course Anaconda will beat any advertised price but you have to go through the hassle (and they may not match/beat the price if one or both stores don't have stock). I prefer to support the guys that have the best advertised price, generally speaking, rather than force the big chains to pricematch.
Service wise I'd rate BCF and Tentworld best. Downunder is very hit and miss - mostly miss - and similar with Anaconda. BCF have the most stores and are definitely the most convenient for me.