Honestly, I prefer buying from the UK. I find better prices than the US-based sites, shipping is roughly the same (give or take a couple $ depending on the weight) and it gets to my front door faster from London. No bloody clue why, but unless I've ordered something from within WA I seriously get it faster from Europe or Latin America, regardless of what it is. So I stay away from domestic glass orders. And China. Takes ages to get things from China.
Mini-story: I once ordered 3 items. One from LA, one from Brazil, one from London. I ordered them all within 5 minutes of each other and picked the cheapest shipping options. All were coming via Postal Service, no FedEx or UPS or anything. The one from Brazil arrived first (4 business days), then London (5 business days), and the one from LA took 12 business days. I could've driven down there to get it myself (and been back) in that amount of time. I've repeated this little experiment a couple times since then, ordering things from various places around the US and the domestically ordered item always arrives last. Unless (as stated above) it's coming from within WA. Then I get it in 2 days, sometimes the day after I ordered.