I bought open 32 bit BCI (8 channel) a couple of days ago, still waiting for it to arrive and I don't have enough time right now to experiment anyway. I just wanted to say that it's a bit cheaper to buy it on Ebay. I saw openbci on ebay several times. I bought new, unopened one for 250GB (~375$). It also has electrodes and conductive paste. Some people have those devices left from the kickstarter campaign, some of them have their research interests changed or something else happened while they were waiting for the device, so those devices are either new or barely touched. In contrast, same device would cost me 450$ to buy from the openbci site and I would have to buy electrodes separately, which cost additional 40$. The only thing I'm concerted with is headware. Right now they are developing the new version of the 3D printable headware. Meanwhile I can't find anywhere which electrode cap to buy or how will I able to manufacture the 3D printable headset when it will come out.
It seems that openbci can support both dry and wet electrodes, but wet are the default, because they provide better measurements. Also there is daisy module, which transforms the 8 channel board into 16 channel. However, I weren't able to find whether it's possible to buy that module separately (on their site they sell complete 16 channel kit). Openbci supports multiple software and it's software support is only getting stronger. BrainBay and OpenVibe are supported; both can be used for biofeedback. Despite that BrainBay is for Windows, it also works on Linux through Wine.