Perhaps this is normal, but I couldn't believe my eyes when I burned my first 15 Mbps ACHD DVD with MF6 (using a Vegas 8 rendered clip without recompression): using Nero Showtime or PowerDVD players, it plays back beautifylly from the regular DVD burner! And with full 25fps, without any compression artefacts.
I always thought some 9-10 Mbps is all a red laser DVD is capable of....