all i have heard are stories of horror with delays with Tiger. and TBH they were all out of Canberra (loads of friends etc that live there). i guess if the price was really really good i'd consider, but then again, i find airports and flying so annoying that i just dont think i would want to bother with narky customer service stricto policy...especially travelling with kidlets and their 'surprises'.
out of the domestic carriers for travelling with kids i found virgin to be the most flexible...

