I think it will depend on the individual needs of the parties... I had FDRS mediation a few months ago and it was a disaster.
The mediator was a bit wishy washy, didn't want to upset or offend anyone, talked too much etc. And we were forced to run the mediation by phone due to covid restrictions (hopefully doesn't apply to you now), which meant it took far longer than normal to get anything done. We spent 45 minutes on the phone initially, then waited nearly an hour for them to speak to the other side, then the mediator came back to us with the other side's proposal which didn't really address anything much in what we had said, and when we asked "Ok, but what about x, y and z?", they didn't really have a clear answer about the other side's position, other than that it wasn't agreed to. I mean, okay, but why wasn't it agreed to? Was there a particular obstacle? The mediator wasn't entirely sure. So that required them to go back yet again to the other side and start all over again with more negotiation and when they finally got back to us, the half day was basically over and all they could do was summarise the other side's position rather than offer any further time to discuss.
In the end, what the other side was prepared to accept/concede wasn't enough for me, so perhaps it was just one of those mediations where the two sides were too far apart to get across the line. But I feel like it was a huge waste of time and money in retrospect. Every case is different and my ex is particularly difficult and selfish and controlling, but I really feel like in cases like that, it HAS to be in person. Our judge who has now ordered (by consent) private mediation for us, after being told that by both sides' representation that our FDRS mediation was a frustrating process by phone, agreed that in many cases, it's necessary to "stare into the whites of each others' eyes", and I tend to agree. If we had the ability to have a conversation, or at least have the ability to interrupt (politely and when appropriate, obviously), a lot of time spent putting forward proposals that were never going to meet the needs/wants of the other side would have been saved. We could have asked pointed questions about what they were prepared to discuss/negotiate, and what was off the table for negotiation, and vice versa. We may not have been able to reach an agreement (and we may still not at this forthcoming mediation), but at least we could get to the crux of the issues more efficiently.
So... there are my thoughts on mediation, such as they are. If you have any control over the booking of mediation, I recommend you think carefully about whether the dynamics of it will be productive for your and the other side's situation and personality. Obviously many factors will be outside of your control (you likely won't get to meet the mediator beforehand), but hopefully you can ask questions about the process before agreeing to it.