I also have my VF-27 pre-ordered through them and rest assured, AmiAmi, being the biggest online store in Japan, gets their items faster (literally on the day of the release) than practically any other online store, HLJ, HS, BBTS, etc... Thy ship out items pretty quickly and I have had no problems with them. (^.^)
However, they usually wait till all your items are instock for the month before proceeding with combined shipping, I'd recommend you send them a message to request immediate shipping once the VF-27 if you go any other pre-orders this month.