I've never bought from them but I have heard of them. Being in the UK it's hard to say if they will ship to USA with signature service. It's a gamble. I placed 2 orders with 2 different US retailers in the last month or so and neither of them shipped with signature service, yet they did back when the new regulations went into effect.
Whether or not NewVaping will charge a fee for signature is easy, just go though checkout and when you get to the shipping page it will tell you. You don't have to give them your payment info if you don't want to.
I've looked and can't find them anywhere else. Sorry.
Be careful, google lists a bunch of fake chinese vape sites you need to steer clear of. You'll know them when you see them because they all have generic site logo that will say "Vape Shop", Vapor", "Vape" or "Vape" with a liquid drop before it. Example vapeeach.com and vaporcheapest.com and vapingjust.com