I saw a thread on a modelling forum when I was looking to upgrade my brush where a similar question was asked (you think I can find it now!!! ). From memory, the brand carried by bunnings is of similar design to one of the "better" name brands (and can use O-rings and needles from them interchangably)...

They were generally saying they preferred to use them becasue they worked well and were easier to clean. They only used their higher quality brushes rarely and only for fine detail work.

Sorry I can't give you a link to anything. And I can't qualify any of that discussion - I never upgraded and still use (I'm sure to the horror of most modellers) an Aztek.