Hey Chris,
As far as ESATA goes with the NVS2525, I found it is a lot glitchier and touchy, meaning it can easily be bumped and stopped downloading or have a hard time downloading all the way through without finding an error. The only time I used the ESATA was for when we were syncing. Also, multi-copy can be very problematic at times, so i definitely recommend single copies if in a rush and have a lot of footage to download.
And in terms of the accessories and running off AC power all the above you mentioned are true. The cigarette adapter worked fine, AC power was the best and i recommend being on it anytime you have the ability to use it because it takes a while for the Nexto to recharge.
G-raids worked wonderfully with the NVS2525. But I haven’t heard of anyone complaining about any other hard drive or ESATA not being really compatible with the device. All in all, I loved the Nexto. I had to use it while doing an on the road for a month, constantly moving shooting all the time TV/Documentary, and it never gave me problems, and made downloading at night much easier!
Hope this helps.
Adam