I know a lot us SK guys are going to IRENE.
Personally, I attend events to horse around and have a fun time with my buddies. I'd love to go a MSW event, but given that my buddies were planning on attending IRENE, it made more sense to sign up for the one rather than the other.
I can't speak for MSW events since I've never attended one, but Lion Claws events are pretty milsim lite. They basically follow the formula of a few hours of play time followed by a break for lunch, more play time, a break for dinner, a short night game and then a few hours of play on the following day. It's significantly more relaxed than a Blacksheep event which puts you in the field for the entire time. Lion Claws events provide time for hanging out, tailgating in the parking lot, shooting faces - a nice, relaxing weekend rather than a challenging event.
MSW is definitely going to provide the superior milsim and war-gaming experience.