All of my concentrates and, separately, the nicotine came packaged in vacuum-sealed plastic. I thought this was an excellent touch; it keeps them fresh if you don't need them immediately and looks nice to boot. I also received a handwritten thank-you note and a little gift, which I was very impressed by. The shipping was very fast, too; 2 business days.
I sent an email to them asking about a certain concentrate being in stock in a certain size, and they replied within 12 hours to say that they'd just done a restock on the website and it was in stock! Again, I was impressed.
My sole complaint with Paragon is that the wishlist forgets things when you add them and sometimes its add-to-cart function throws an error and you can't add it, so you have to go find the concentrate. It's a rather minor niggle, but was annoying nonetheless.
The prices, though! I was paying almost double for my concentrates before I found these guys, and that's really reason enough to order from them again even without the rest of the goodness.