I am noticing that the price difference between buying on AliExpress and locally (in the UK) is not so much! I only just started shopping for an Ultegra 12 speed Di2 full groupset, and I do not know what prices were like earlier this year.
I can buy for 1057GBP +35GBP shipping from anrancee and risk additional customs tax. Compare this to local UK price of 1175GBP with free shipping and no added tax.
For me, the prices are really good in the Anrancee Store. I’m based in Switzerland, and the Shimano R8170 ULTEGRA Di2 Electronic Part (upgrade kit) costs 800 CHF / 992 USD including shipping (without coupons). With coupons, I can save another 98 CHF, so the total comes to around 700 CHF / 868 USD for the Shimano R8170 ULTEGRA Di2 upgrade kit.
The Shimano 105 R7170 Electronic Part Groupset (FD R7150) comes to about 520 CHF / 645 USD in total.
That’s roughly 200–400 CHF cheaper than buying it here or from Germany.
I contacted Anrancee support, and they confirmed that they can adjust the declared value on the parcel for me, so I’ll have no import tax or a very low one. Support was really helpful and made the items for me available to order from Switzerland. Beforehand I couldn't find the groupsets because shipping to Switzerland was not available and I was only able to see them over the direct link.
However, I agree with what others have said — if you have any issues with the groupset, you probably won’t be able to claim warranty, which is the major downside.