I have this lens and I use it a lot. It rarely (if ever) leaves my camera. I use it mostly for wildlife photography. It's a good lens... well-built, smooth focusing ring, mine hasn't shown any lens creep, and it tends to be sharp throughout its range. It is a little slow, so that might get frustrating, but it will give you an opportunity to perfect your manual focusing technique. Still, you might miss some shots unless it's really bright outside.
I've been fairly happy with my copy, but as of late I've been seriously considering an upgrade.... something a little faster, and with a longer range.
If I were in your place, I'm really not sure what I would do.
When I bought this lens I paid less than $300 USD... I'm not sure I'd be willing to pay $600 AUD. Then again, I'm not sure what else is out there for you.
Nikon D300 / 35mm f1.8 / 300mm f4 / TC-14E II
Pentax K200D / DA 18-55mm / DA 55-300mm