The worst thing about our sparring is people who come in thinking they can fight, ( I have to say it's always a man). They don't realise, or don't want to realise that they have to learn an awful lot of techniques to be able to hold your own in an MMA fight let alone win. The standup is karate/Muay Thai/TKD using wharever moves work, we have people with a wide variety of experience so we continually learn new moves. I imagine any of you here who do a traditional stand up style would feel at home with the standup yet some come in thinking it's just a matter of throwing a few punches and kicks which is easy "coz they've seen it on the tv ot I've had street fights you know!" they have the same attitude to the floor work well it's just rolling around cuddling each other isn't it! When I've done traditional martial arts people like that tend not to join, though I think sometimes there can still be an ego problem there.
The best thing is that's it's like a game of physical chess, your mind moving as quick as you body (hopefully! at my age there tends to be a bit of a time lapse lol). When we spar we have to adjust what we do to what the other person is trying to do, if they are good at standup try to get them down, and vice versa. We don't intentionally go hard on each other, and I don't think it's many harder than a traditional full contact karate club, it's just more contact than most perhaps. I have heard that old style Judo clubs are/were pretty full on though!