hrmmm i dunno id rather rent in langwarrin than karingal as it seems real old and run down (but that could be a good thing?)
Tenants make their selection based on practicality, amenities and affordable rent, not whether a suburb is a bit old/run-down. Things like schools, shopping, transport and recreation are key.
Footscray CBD and environs is a run-down, grimy and stinky hole but this does not stop people from renting there due to its extreme proximity to the CBD and the entire western suburban area.
If you're an owner-occupier with an unlimited petrol budget and you like the area then Langwarrin will be OK. It probably won't appreciate as much as Frankston South (or most other parts of Frankston) but that may be less a consideration for an owner-occupier if there are personal or family reasons to buy there.
But at the lower and lower-middle end of the rental market there is a good chance that the tenants will have only one car between two adults. You can easily get by with no or one car in central Frankston. Karingal is possible with some sacrifice. Langwarrin is almost impossible.
A slightly run-down property (compared to the others) in a handy street might end up being the best buy of all, from both a rental and improvement perspective.