Maintenance (Specialist) Plan Experiences?

Does anyone have experience actually utilizing the maintenance plans? Low or mid volume? Do you find that it does, indeed, more or less keep your FTP constant? Have you been able to pick back up with a build phase without adjusting your FTP?

Anyone have experiences with how adaptive training operates around the maintenance plans? I saw another phase where someone was asking whether they get adapted or not, and nobody replied.

Would love to hear the experiences of others regarding these plans!