While these guys do freak me out they have never hurt me and eat other insects I would rather not have around so mostly, if they just chill out i will leave them alone. They are one of the few insects that if they are in my house i will try to get them out alive instead of killing them.
One time I saw a showdown between a big Mantis and some geckos who thought they could eat it. They were wrong and the mantis knocked them off the wall with his spikes. It was fun to watch.