Staying near Hardy's so have only looked at the changers between the Hyatt and the local market.
There are 3 more official looking money changers which have a "safer" feel to them.
The 2 I ca really recommend are BMC which is the one with the big USA dollar on the wall outside.
The other is fairly new, it was here in April but not when we came the year earlier. Can't remember the name but you can't miss is, almost directly opposite salon Rudy.
The one I will now give a wide birth to is Pt Dirgahayu. You also can't miss it as it has a green large board outside with LED exchange rates. When I went to change some money I noticed the rate written on the slip was different to that on the board, when I mentioned this I was told the rate had changed. Took money back and left.
Hope this is helpful to some of you.