Smartshoppersinc has higher list prices for ups shipping vs. truck freight in addition to a shipping charge that is based on a percentage of the order total but no additional hazmat charges. Some items they sell are truck freight only. I have ordered several gallons of primer and clear from them and quart sizes of reducer that have all been shipped ups. They use special clips on the gallon cans to make sure the lids stay on and use packing tape over the screw on lids.
Spraygunworld didn't list that they can't ship the large sizes. After I had placed an order they emailed me the next day telling me they have to charge extra but that I could email them back and request quart sizes. They wouldn't respond to the email and I had to call them the next day to get the order changed they had the entire order on hold waiting for me to tell them something. From then on I just started ordering quart sizes. The only paint I buy from them is house of kolor base and reducers. I use primers and clears purchased either locally or from smartshoppers.