I had high hopes that the new Tascam X8 would be an upgraded version of the H6. Same channels, smaller, cell phone control, etc. But they f'ed up the design and its really a four track recorder with two detachable mics. Can't just do 6 channels direct in. Boo.
I've had the same thoughts about doing the IR in setting the sync markers on the Tascam 2D. When I experimented with it, there were minor differences between the decks. So it could be within a 100 sample difference in either direction. Basically useless for time alignment...I need it down to the sample.
If Tascam is able to fix the limitations of the X8 in firmware updates (not that hopeful), it would be an excellent upgrade to the H6. As it is, the H6 is still a nice size for the number of channels. I did a bunch of shows with the six channels on the H6 and then using a Tascam 2D for two additional stereo inputs. I like the potential of the Zoom H8 for a potential 10 tracks, but the physical design on that one is nutso.
And yes, Adobe Audition 3's time stretching algorithm is more accurate the the later versions of Audition.