I rarely buy from LBS because the few that are a reasonable distance from me have owners who not not very customer service oriented unless they are part of a racing team who spends mucho danero. They usually don't have the part/supplies I'm looking for and when ordering can take weeks to arrive.
Counterfeit products exist everywhere and there is always a risk. I have never purchased form Aliexpress, though have been tempted a few times. If the price is right, I will order through Amazon. Why? Because their customer satisfaction policies are great. I've heard/read stories about Ali which make me believe, once purchased, you're on your own regardless of the problem.
On a related note. Online bike stores have mostly been positive experiences with a few hitches. Recently, I was shopping for a seat post. I sent an email to the online store describing the diameter, length, setback, material, etc. Asking what is available. They replied, they cannot recommend one brand over another! Is this how they do it in-store?