I don't think there is a pattern. Someone can present perfectly, have a perfect rental ledger and references, and still turn out to be a dud tenant.
One thing I have learnt from working in agencies (I'm a property economics student - have worked in real estate admin for 5 years) is to never make assumptions about the type of tenant someone may be based on how they present initially. I take how someone presents as a grain of salt - if only all PM's did this too.
The worse tenant that comes to mind was a divorced developer that was approved for a beach front penthouse at $1200 per week. 6 weeks later he stopped paying rent and did a runner. The PM department had a lot of trouble locating him, but applied to take him to CTTT for what he owed which was about 14K. The CTTT then contacted the PM in writing, stating the guy had declared himself bankrupt and therefore nothing could be awarded. I don't know what happened after that as I left the agency.
Another agency I worked for had a young couple (female was 19, male was 23) that were hassle free for the first 6 months of their tenancy. After that, they were in constant arrears, were sent termination notices but always caught up to avoid the CTTT. The premises required some repairs, they were a nightmare to deal with during this time. The owner then decided to sell the property and they kept refusing access to the sales agent and wouldn't allow the agent to take any internal photos. After 3 years, the owner finally decided to give them 60 days notice. They didn't leave on time, so a possession order was obtained. They left after this, but the place was unclean, carpet was stained, a couple holes in the wall and some furniture left. Out of interest I went through their ledger after they vacated and realised they were in arrears (varied between 1 - 4 weeks) for 2.5 YEARS!!! I don't know what the PM's were thinking keeping them in there. Anyway, coincidently, I found out through a friend who works as a PM at another agency that he leased a place to them back in September 08. As they had no rental history (haha, I wonder why), they paid 6 months rent upfront. Apparently the place was abolutely immaculate upon inspection, they haven't been a day late in rent since their fixed term agreement finished in March and he hasn't heard boo from them.