It depends how serious you are about your business.

Ive imported by myself previously from India and China for a business outside of Ebay - I would never use Alibaba or aliexpress to buy anything - they are simply too expensive compared to what is available in these countries. I found most of the products I got direct from wholesalers in China and India were 3 to 5 times more expensive on Alibaba.  It might seem cheap to us, and our economy, but they do not work on our economy, and most of it is inflated "tourist" prices.

In saying that, if youre not looking for a full time business, buying from Alibaba can still make you a quick profit, just not as big as if you do a little more research.

If you do buy from Alibaba, only ever buy from GOLD members who have been on the site 2 years or more. They have a little gold coin with the amount of years they have been on the site.  Gold members are verified - they have identity AND business licenses checked. Its not fool proof obviously, but it should make your dealings easier than had you used non verified members. I also found they generally have better English skills and have more experience with dealing with Western customers (not always, but in general).  

Also, be really careful what you buy. If youre buying a large quantity, get a sample or two first to check for quality (and the chemicals used on things like clothing etc because they honestly STINK and youll get complaints, and some are actually illegal in Australia). Also, check your competitors on Ebay - items from Alibaba have mostly saturated the market - no point in trying to sell something that 100 other sellers are selling.

Also, if you only ever import under $1000 worth of stock, you wont have to pay GST / duties on it.... its much safer (thats going to change un Jul 2017)..... but be careful with customs - its easy to do, but it can be very expensive and you need to add this onto item cost, and if you try to go under the radar and get caught you can be in big trouble (more so if you dont have an ABN and do your taxes properly).