I haven't had the chance to visit any of them. From what I have seen, SOAS seems to be quite backward, not modern, and people there seem not to be that friendly as SOAS would have liked you to think.
When in it comes to bath, everything is wonderful except for the fact that the university is mainly a scientific subjects uni, so compared to SOAS or king's i don't know if it would be worth it.
Finally, KCL is great, the course is really really good (as the one at SOAS, but here the facilities seems to be amazing). On the other hand, when it comes to have a look at unistats, KCL doesn't seem to do a good job..