I've loved visiting and exploring Réunion on this group hike with MBA and would highly recommend it.
This island is such a special place. On a relatively small area, it offers a huge variety of different landscapes, sceneries and climates. You get to experience everything from steep mountains covered in tropical jungles to a barren landscape surrounding one of the most active volcanoes of the world. Every day offers something new.
It's certainly a challenging hike. Different group members struggled with different days. I found the first few days of Mafate very hard because it was very hot and the climbs there are incredibly steep; so steep that a lot of the trails are just seemingly never ending staircases! Others struggled more with the latter portion of the hike. But each difficult section rewarded us with the most spectacular views at the end of it, so although it was difficult, it was an incredibly enjoyable experience and I'd do it again in a heartbeat.
The only constructive feedback I have to say is that I think a group of 12 people would possibly be too large a group, at least for 1 guide. We were a group of 8 and that felt a good size.
The communication through Clément and our guide Fred was excellent. They were very helpful with organising logistics such as transfers and answered lots of other questions ahead of and during the trip. The roadmap that was provided by Clément ahead of the trip was absolutely brilliant and have a very clear idea of what to expect from this hike. Fred is extremely kind and patient as a guide and had lots of interesting facts to share with us along the way. He also had very good insight into the needs of the group. This hike is very long and challenging, but is also modifiable at various points along the way, and Fred made excellent judgement calls for when an adjustment to the programme was needed to keep it manageable and enjoyable for the whole group (e. g. doing the Piton des Neiges summit as a sunset rather than sunrise hike the day before originally planned and taking a car transfer for the last couple of kilometres on the day after the summit hike to the gîte in Bourg Mourat).
Other group members felt the trip was harder than they expected, but I personally thought the MBA listing was representative of the trip and how challenging it would be. Maybe mentioning how many steep staircase paths there are especially in the first half of the trip would be helpful, because a lot of people in our group were surprised by this and found it difficult.