I've used ABC a few times to do both supply+fit, and supply only and always found them to be better priced and better service than Kresta / Vista. Kresta/Vista are fine but seem pricey (at least on the stuff i wanted).
I believe Kresta and Vista are the same company.
I usually go in and just buy the blinds from ABC and fit them myself - really saves you loads.
I have used blindsonline.com.au before a couple times as well as my ppor, quality is great, saves heaps, obviously diy install.
Edit - need to be buying more than 1 or 2 to make postage to WA viable though.
Professional, and cheap, they have done 3 of my rentals. I always get the builders choice which have lasted 5 years in one of my rentals without any problems.