Still holding off on any upgrades myself. I really
still believe that he should be designing something more like the CE2 (as BigBulli has done, a repairable CE2). It is the obvious upgrade path in my opinion; the airhole needs to be located underneath the coil, the side mounted airhole design is really pathetic. The cartridge design with filler is not good, a liquid tank is much better and generally holds a lot more liquid.
It is still ugly, I think he should be looking into making a whole new design where the atty connection is extremely slim so the tank/shroud that screws on can be interchangeable (small/medium/large designs). The possibilities are endless, but the current design has fatal flaws that will always hold it back. He should really be looking at how to do it without the wick also, but I assume he still has a monopoly on that as no one has discovered what it is he is using?
I still love my Bulli a2, still use it all the time, however, I am not going to spend more money on it until he improves on the points I made in the opening post of this thread over 6 months ago