Buying directly from Alibaba VS negotiating with supplier VS freight forwarder

I’ve heard and seen a lot about how expensive and confusing it is to buy from Alibaba. Which seems to be very true. But there seems to be plenty of listing that have “alibaba guarentee”, where it looks just like buying from a normal retail store online. With a “guarenteed” delivery date, and relatively cheap rates. For some items, I’m getting free delivery even with a batch of 100 pcs (or is it a promotional offer for me being new?). Which is a very significant decrease to the total cost.

-So is there any disadvantages of buying through alibaba guarentee? Any reason for me to not by through it? seems to be significantly easier (and potentially cheaper)

-Would a freight forwarder be cheaper than using the shipping provided by alibaba?

– Is shipping through alibaba’s provided shipping straightforward? (e.g I don’t have to worry about customs and stuff).

Thank you in advance for any help