Yes, good point. They have better integrated graphics, guaranteed support for the new 6 core processors and integrated sata 6g. I would go for them if 1. I needed good integrated graphics 2. I needed the most future-proof board possible or 3. I was planning on using SSDs.
You can get older boards which are guaranteed to run Thuban with a BIOS update, and I don't think it will change with later CPUs. Therefore I don't think 800 series = more future proof, except for SATA 3.