I've got 7 baby short necks! had no hassle at all! just if your keeping them inside,try and setup a little tank outside so they can get natural sunlight they will grow better! easy to feed and very fun turtles to watch!
I started with shortnecks there's a bit to get your head around at first but they're awsome - I had 2 Krefft's then got a Maquarie and they're all thriving and doing really well, checkout care sheets on australianfreshwaterturtles.com.au they have care sheets on there that are brilliant
My personal preference is for the long-necks. They seem to be more settled in general and as long as you do the research first they are not that tough to look after.