400i isn't accurate unless you equate recessed midrange + treble boost as accurate.
MrSpeakers Mad Dog's quality was debatable back then (better than hobbyist T50RP mods like Thunderpants or the original ZMF headphones I guess but definitely worse than the Enigmatic Audio's Paradox).
With every company releasing an orthodynamic headphone, its really not good. At the end of the day, its still a Fostex T50RP mod with some questionable tuning. Worse than the newer ZMF modifications, still worse than Enigmatic Audio's Paradox, worse than a lot of new releases from major companies like Oppo's PM3.