I think there are a few potential issues. Being in Mexico, it's an international purchase which means you have very little to no recourse if an issue arises. The big, trusted retailer in the UK that just folded up shop last year taking thousands and thousands of dollars in deposits shows that the unknown can happen anytime.
There's no shipping quote so who knows how much they'll charge to ship this to the US. At the end of the day, excluding shipping, it's only $30 more to order from Sideshow and if you wait a couple months and use a $20 coupon, it's $10 more. I'd much rather pay that $10, or even $30 if you don't want to wait for a coupon, for the peace of mind that I get with ordering from Sideshow in case something goes wrong.