‘Posh’ and popular real estate in Bendigo generally is either on high ground, near parkland or other popular /convenient amenities, in an area where all the houses were built in a similar era(Victorian or mid century modern) or they are within an urban ring of the CBD. Other comments here are also a good guide.
I've just spent a year renting in Long Gully and my area was fine. Neighbours were lovely, and although there are some goons who seem to delight in driving too fast and loudly at 11pm at night, that would be once every now and then, certainly not as a continual thing. I'm only leaving because I was recently retrenched, but like everywhere, look at the immediate surroundings. You can tell a lot from neighbouring properties.
Generally they are low socio economic areas and attract the typical problems associated- unemployment, crime etc