I am new to vaping like you, and like you I started with the electronic cigs from Greensmoke(similar to Blu) but then bought a simple ego twist/protank combo shortly after, and it took my lungs a few weeks to adjust, now I am just starting to get used to my mech mod and RBA,. If you are like me, you will need time to adjust to the more powerful atomizer At first, I wondered why anyone could suck on those hookah things when my Greensmoke ecigs worked so well, but now I never touch them anymore, as I crave my Protanks and RBAs more.
I know you've already spent a grip of money but might I suggest getting a simple, inexpensive ego twist battery with a protank 2? They are easy to use and easier on the lungs. Your going to need a back up anyway.
The others are right though you need to let the flavors steep but I wouldnt give up on MBV juice though just yet. I love their Hawk Sauce , I am also beggining to crave Citrus Bliss and Smooth Criminal from Ahlusion more and more but despite everyone pimping Ahlusion, some of their more popular flavors I found disgusting like Sasparilla, Boba Tea and Pineapple Cream.