I found Commonwealth are good for personal banking, but not so good for business banking esp if you need to set up merchant accounts or need to get in touch to sort things out.
The business centres are for proper companies (not sole traders) and if you want to set up a merchant account you have to do it dealing with a centre you can only ring and which I had a terrible time with. Waiting time to talk to the business services 10 mins+ (I thought I had called DIAC by mistake at some point )
Also they required several thousands in security for the c/c reader. So it depends what type of banking you need... I am now with NAB and very happy.