I have finally decided that there is absolutely no good reason to use TDM hardware if ProTools software isn't being used. If Logic is the front end, then it works vastly better in CoreAudio mode than trying to use the confusing and limiting fustercluck that is DAE/DTDM. Even using the HD hardware with Digi's horrible CoreAudio drivers yields better results in many respects (but only 8 I/O max). ProTools HD is a fine [closed] system that works well if money is not an issue. But not when using DP or Logic. For the same money you can get a better sounding Apogee Symphony system, with lower latency (which is saying something) with more I/O, with a UAD Quad card or two, MacPro 8core with 16GB RAM, lots of 3rd party plugins, etc etc etc. I actually priced one out and went crazy on all the extras and it was still two grand less than an HD rig but it would totally blow it away in every way..... except you can't use ProTools software. Sure, there might be some TDM-only plugin you can't live without, but if you had started from scratch there are definitely AudioUnit equivalents (especially UAD) that are amazing but maybe in a different flavour and if you had started out with these you'd hate the fact that there is no TDM equivalent if you suddenly had to move to a TDM rig.