Yes, the rosetta 800 and 200 sound a lot like the Hedd, but without the tonal and sound shaping controls used by ME's. The AD16x and DA16X sound a little bit better than the rosetta 800/200 IMO. you are already summing analog and probably would not want to add any more harmonics to the mix. I would leave that for the ME. So the Hedd with only two channels is kind of a bottleneck for the way you work.
Rosetta 800 works great as a front end to PT and it sounds great. nothing like the psx or the first generation rosetta. i use it in place of a PT interface. PT sees it as an 888 when you use the optional x-digi-mix card. The rosetta is a little more expensive than a hedd when you factor in the cables, and the digi card, you're looking at around $4000.00. But you have 8 channels of very high quality I/O and digital options. For 16 channels of I/O go with the ADx16, DA16X combo. about $6k for that option.
just some ideas. If you like the hedd, get a Hedd. I just wanted to let you know there are some high quality apogee options designed specifically for PT and multi-track DAW users. if and when you upgrade to HD or any new PT system or native DAW, you simply swap the digi-card for the newer one and your hardware I/O migrates with you.
Regards,
brett