My experience has been all "very positive". Recognize that aliexpress only introduces you to thousands of different sellers in Asia. THEY are not the supplier for any of the goods and only facilitate the items for sale. Naturally items shipped take time... they are ordered from Asia and shipped to what ever your mailing address is.
I have ordered over 90 things from Aliexpress and shipped to Canada. If ever there was a problem, it was because I did not read the instructions myself. The sellers I have ordered from were more than accommodating when it came to questions. That is not to say you cannot run into a poor one when ordering from such a large catalogue of suppliers.
All of the vendors are interested in selling their goods and most importantly relying on a positive review, which in turn, motivates them to give the best possible service they can.
Aliexpress has allowed me the opportunity to own some items I probably wouldn't buy here because of the cost factor.
The most helpful advice I can give is to try them for yourself... read the descriptions very well and be patient for it's arrival.
Probably sooner than later our government will create a way to stop or increase the cost of these goods to get their share, so I would act now while the going is still good!