There are so many nappies brands out there, it can be a little overwhelming. I started off using huggies and brought the boxes when on special (For newborns apparently they are the best).
I have tried about 5 different brands and from what I have noticed, there isnt much difference between nappies they all pretty much do the same thing. I found Aldi nappies were small so if you do want to try them get the next weight size up. I think I used the 4-9kg nappies and they were too small around the legs for E who was only about 6kg at the time.
My motivator is price. I work it out per nappy as there are different amounts in different packs. At the moment I buy the Woolworths unisex nappies. They work out to be around 27c (for 4-9kg) as apposed to 30-40c each for other brands and find the sizing great. Have a look around when buying nappies, try different ones and go with what works for you and what motivates you and your lifestyle. And don't forget to look out for the specials!