In case you are young and want to risk a long time bet, you should probably go for implantable electrodes in your BCI, but do not expect the fine-tuned, thought-controlled robot arm within the next few decades.

In case you are a medical professional and want to help diseased patients now and not somewhen in the distant future, you should rather invest into EEG technology and leave the real freaks with the electrodes. But keep an eye on them...