I
buy unflavored for DIY mixing. I get mine from myfreedomsmokes.com, as their quality is amazing and the glass bottles they use store very well. They often have incredible sales, and I wait to buy until then.
Unflavored
juice will still have a taste, its the nicotine that can be tasted. It's pretty bitter, tastes similar to a nicotine lozenge, only a bit weaker. Flavors mask that taste most of the time, but you can taste it if its unflavored, especially if you vape around 20mg and up.
I use 100% VG, not sure if that affects the taste vs PG or a VG/PG combo.
If you order unflavored, you can always add pure flavorings from Perfumers Apprentice or even get some water soluble Lorannes from Walmart to add flavor to taste (as weak or strong as you like) You might prefer that to premixed, its cheaper (WAY cheaper)