I'm in the same boat as OP... I bought the blu last Thursday, rather on a whim, to see if I liked it any better than analog smoking. The first cartridge lasted me for about two and a quarter days. I normally smoked about 16 analogs a day. I liked it immediately, but realized I would want better equipment. Until that gets here, I have the blu to get me through and I'll have it as a backup.
I don't really get the *hate* that I'm seeing in the vaping world for blu. If it is viewed as an easy intro to vaping, isn't that a good thing? And like any product, caveat emptor (buyer beware). The fact that blu is paying for nationwide advertising to make vaping more mainstream seems like it'll be helpful, as well, to get the word out and more people off of analogs.
In reply to the OP, the High level cartridges that my set came with are supposed to be 13-16 mg and last 250 puffs. For the sake of averages, let's call that 14.5 mg and divide that by 250 puffs. That gives us 0.058 mg nicotine per puff. The Marlboro Ultra Light 100s I smoked purportedly have 0.5 mg per analog. That means that I should puff 9 (8.62 to be exact) hits to equal about one cig. To take that one step further that means that each cartridge is equal to almost 28 cigarettes at nine hits per. If you want to know what the levels are for your particular brand, just google the name and nicotine content. You can do the math.