Hello there 
Yes indeed, it is a replicated actor component which can be pretty bandwidth / performance intensive if done wrong.
I didnt specifically tried 100 actor components but I tried spawning lots of AI’s and player characters with some skills.
CPU performance is OK, but they do cause some network traffic.
If 100 characters have 1 skill, skills won’t be your performance bottleneck. If you have several entities in the game with hundreds of skills, yes it might be unplayable. What kind of setup have you in mind? Something like WoW where every player has hundreds of skills? I think this is hardly doable with MCE.
Little update as well:
I spotted new bugs which I’m trying to fix. I’m trying to get something as smooth as possible so I’m still delaying tutorials & commercials.
Good luck and have fun everyone, see you in the next update