John,
Visit
www.avsforum.com and nose around. There are specific boards for cities and cable franchises.
I follow the threads for Adelphia in Los Angeles. While I do not have a Moxi (I have a Motorola 6200 HD box, the non-DVR), the posters trash it continuously, and the main focus of their wrath is the "guide" disappears regularly. However most people blame Adelphia, since on other systems it often works better.
Apparently Adelphia is doing a new firmware upgrade to the Moxi's next month. However this doesn't necessarily mean anything to you. And, after reading about 300 postings on the Adelphia Moxi, no one said anything about third party software.
Craig