If you want to be able to customize your PG/VG mix, then you'll want to go with a vendor like Copper Creek or Viking Vapor. I haven't personally tried Copper Creek yet, but I'm waiting on my first order. Many great
reviews on her
juice.
I used to order from Viking Vapor all the time, they're not bad for the money and will custom mix the VG to PG ratio (as does Copper Creek). However, VV's VG is very thick, almost too thick, so it does tend to be an atty killer. Still, they have a ton of different flavors, quick shipping, and you can customize your mix for VG/PG, flavor strength, and throat hit.
I think that Virgin Vapor makes some high quality
juice, but some of the flavors mixed on her "house" base (vs the ecoPure base) are hit or miss. Some of them have tasted somewhat bitter to me (strawberry lime cooler), and others are sort of perfumey (Kir Royale). However, overall her quality is top notch (and I did enjoy the Banana Nut Bread juice quite a bit). The EcoPure base is fantastic, but a bit pricey (due to the fact that the EcoPure base is pricey). I was very very impressed with the buttercream mint flavor.
The coffee flavors from Virgin Vapor are really quite good as well, and are extremely clean so they don't gunk up attys and cartos.
Tasty Vapor makes some fantastic juice, the "Geoff's Blend" is outstanding - tastes a bit like Juicy Fruit gum. PG disagrees with me, so I can't vape TV juice all the time. If you don't have a problem with PG juice, then definitely check out TVs juice. The only flavor I did not like from them was the Almond Horn. I also recommend the Pineapple Orange Banana flavor - it's very tasty, "juicy" - tastes just like the real thing.
Alien Visions is my current go-to vendor (although they are temporarily closed due to some real-life issues, they will be back online very soon I'm sure). I am a big fan of their juice, namely "Gorilla Juice" which is a light toasty tobacco with hints of caramelly toasty banana.