Hey Nelle,

Yep I've been buying from Ezibuy for years now. Even back when it used to be called Myer Direct ha ha.

It can be hit and miss, you really have to look at the photos (the website is good as you can zoom in) and read the descriptions of what the fabric is (tip - don't buy anything 100% cotton as it will stretch all out of shape!).
They have sales a LOT and often send random discount codes, free postage codes etc. I usually do a google search before a purchase if I don't have a code myself. Just this Saturday I ordered a dress using a code for $20 off a purchase of $75 or more.
If you register with them (free) online you will get the emails.

As for the 'brands' - I like Grace Hill for office clothes. Sizing is usually pretty good. It is a little more pricey but I tend to just buy stuff when it's on sale. Emerge and Urban are the younger brands. Emerge has heaps of cheap dresses but I've never found the quality to be too great.
Capture is a slightly more 'mature' brand but has good basics.

I've always found the customer service to be great, never had a problem. Normally I'll wait until I want to buy a few things at once (postage is a flat $9.95, there's an express option too). Keep in mind that you can return items that you don't want (obviously with all tags still attached etc) but you do need to cover the postage yourself. You'll get a full refund of the purchase price.

Anyway I've gone on long enough - I'm a big internet shopper so I do love Ezibuy!!