I only do duos or the occasional trio (mfff). I ses sp to fulfil difficult scenarios in real life.
I mean, threeseomes are not that easy to come by single, and in a couple I find it often gets messy.
So easier to get sp's that enjoy each other and are truly independent.
I also find they are usually more relaxed in threesomes. Perhaps it has to do with power dynamics, and let's face it, in this line of work, they probably don't meet tge nicest guys 100% of the time, so when they get a bad apple, easier to deal with it when they are two. But I'm just throwing an hypothesis, perhaps sp could chime in here, as I'm definitely not the receiving end expert.
That being said I also had disappointing duos. No Interaction between them, or obviously superficial.
Now if I could find the wholly grail... Two independent pregnant women willing to do a three some, I'd be in heaven!