I firmly believe that Tinyboard is very secure. I can't say much about Wakaba or TinyIB because I haven't really used them much.

In terms of speeds, I did some basic benchmarking a while ago: http://tinyboard.org/wiki/index.php?title=Benchmarking (not including Wakaba). Of course your initial thought would be that my results/tests are biased, and I don't care to defend that. It should be noted that not all functionality was tested, not all conditions were tested, and there are some inconsistencies with the results so they are to be taken with a grain of salt.