I started using the original Blu around 2 years ago and have been using their product ever since. The introduction of the cartomizers was a major upgrade both in terms of overall performance as well as vapor production. Once I got serious about totally quitting analogs a couple months ago, I bought the Premium 100s starter kit and have been using it since. Once again, I was rewarded with a total product upgrade, as the 100s unit addresses almost all of my gripes from the previous mini sized model. Batteries last longer, led indicators eliminate battery charge guesswork, and the vapor production makes the smaller units look sick in comparison. The "social feature" doesn't do anything for me, and I kind of doubt that it actually works. If anyone is considering a Blu, I would recommend just paying the extra few bucks and getting the 100s kit, as it is superior to the standard pack and is IMO what the initial offering should have been.
Two things, though. I recommend doing what I have been doing, which is to invest in only a couple packs of Blu cartomizers and one bottle of third party juice of your choice. The cartomizers can be refilled quite a few times before they go bad, and this will ultimately be cheaper than purchasing more pre-filled 100s carts, which it seems are not offered at retail outlets quite yet. Blu offers a "free" shipping option, which takes weeks, and jumps up to a ridiculously expensive shipping option from there. Save yourself the frustration and FYO, ordering new ones only when the existing carts are no longer usable.