Wrote a bit on 700 series here:
http://forums.hardwarezone.com.sg/showpost.php?p=54865568&postcount=7949
So far this is what I gather of 700 series:
- Advance Cleaning Head = plastic shield around yellow bearing to block hair
- Powerful vacuum = Aerovac 2, which has dual HEPA filters (~50 cts coin size) situated left & right of bin
Like current Aerovac, there's no bottom squeegy, but I do believe suction will be stronger cos the HEPA openings are small compared to current Aerovac with entire bin width as opening. Small opening = high suction
- HEPA: since iRobot dares to call it HEPA, then I believe there's a strict design to follow:
http://en.wikipedia.org/wiki/HEPA
Different from Robot Add-on HEPA filter, which some reviews say suction dropped:
http://www.robotaddons.com/SearchResults.asp?Cat=22
- 7XX dirt detect (Persistent pass) = back & forth combing motion to remove fur balls from carpet
Application: Carpet + shedding pet
- 5XX dirt detect = mini spot mode for sand-like debris, not activated by fur balls
Application: All surface + sand-like debris
Conclusion: Low significance since most households are hard floor where fur balls get swept up in 1-pass by 5XX
- 7XX battery life extension, I believe this is basically v7 firmware, so Roomba 5XX that's been v7 OSMOed or manufactured after Jul 2010 is as good