Aliexpress is US-based sellers with US-based warehousing so you get it directly in the US. The better deals are on alibaba outright for Chinese consumers.
Of my 140 orders over the last two years on Aliexpress, only one has been originated in the US (California, to be exact). All but a few of the remainder were from China. I reside in Colorado. Mostly I buy hobby electronic components, chemicals/substances, and the occasional household or automotive item.
I've used Alibaba.com as well, but the payment methods are far different and it's a more risky situation with fewer guarantees. That service I use for high-value orders after a thorough vetting of the seller. Mostly commodity items like a pallet of green coffee beans, or weird chemicals in unusual quantities.
Sometimes an order on Aliexpress will be large enough that I must consider negotiating with someone on Alibaba.com instead. Negotiations happen for me on Aliexpress as well, but the sellers on Alibaba.com seem to have greater latitude in not only price, but also packing, shipping, and handling to destination.
