Most likely due to the fact that McIntosh is more synonymous with speaker rigs (full blown audio exotica) while the HI-FI Man brand is associated with headphone tech.
Shame really considering the McIntosh pedigree.
Very true SD, you really need your own ears to decide as in all things Hi - Fi (as you already know I'm sure) . Yes the 800 can at times be a tad bright but for pure instrument separation it cant be beat. Give it an audition with the Classical genre when you can.
Agreed. As mentioned you can always upgrade DACs , amps and all that good stuff as time and $$ allow. No rush. Be rest assured though that you are getting one mighty nice hp to start things off. It's a great start. Besides, simply based on your current amp / DAC budget the O2 + ODAC will probably do nicely.