You need to be aware that taking the FedEX UPS DHL etc . option will greatly increase the cost ...
Not only because of the actual cost of Fedex UPS DHL shipping but because on top of what you will pay to the US
shop (cost of products plus cost of shipping fees) you will be charged AGAIN on arrival ...
When you receive your products Fedex DHL etc will charge you customs fees -in Europe that's usually VAT at more or less 20 %- on the cost of the actual products PLUS VAT (20%) on the shipping fees PLUS Fedex UPS DHL etc. will charge an additional "processing" fee of approximately 20-25 euros (here in Euro-zone Europe,dunno how much it will be elsewhere but they will always charge a "processing/paperwork fee").They will contact you on arrival and you will have to pay this to be able to receive your parcel..
Some countries also have "import" duty on certain products ,which is an additional customs fee that needs to be paid (France doesnt have import duty on eliquid,just VAT, so thats one prob I didnt have but many countries do...)
Example= I recently purchased just under 50$ of eliquids from an East Coast store and DHL charged me an extra "surprise" 35 euro on delivery so that almost doubled the total cost for me....and youre pretty much STUCK at that point arent you... just to retrieve your already paid for liquids you HAVE to dish out this surprise extra cost or else lose everything!
THATS probably why most vendors use USPS... the customers probably request it!
USPS will be slower, certainly but their packages usually (almost always) "escape" customs and so arrive without any extra costs beyond what you already paid to the US store on checkout ....
Fedex DHL TNT UPS
always BRING all parcels directly TO customs so you dont have the "luck of the draw"

.....
I receive USPS first class international in approx 8 days.
Just wanted you to be aware of all this .If you need your stuff in a hurry,fine, but be aware that it will probably almost double your costs with "surprise" fees charged by your local postman or by the courier service upon delivery