This can depend for me personally. I mean, some models (especially studio ones) will PM people, whether they ask for the PM or not. So that is part of why they are in PM BUT in Pm AND split camming, it's like some models forget that other people are talking; public, pm, other sites. They get so immersed in one conversation (PM or another site) and forget about everyone else. That for me is annoying. I mean, you see them laughing, giggling etc which of course is great BUT it excludes everyone else and makes them leave. This is why public chat is always best unless it truly is something specific - everyone involved = much better and people will stay because they are chatting and 'bating.
So whilst on one hand I don't mind because the model could be in a nice/good conversation and not be bored, on the other side is they forget about everyone else and/or are terrible at juggling.
I think if you're only sticking with 2 sites it's ok though. It's the poor models that are with studios who literally have 6 or 7 open. I really feel bad for those women. They are doing what they are told yet potentially losing a lot of custom due to so many.