I've had TWC, or its ancestors, for decades, and added RCN a few months back just for its HD tier (2 HDNets, ESPN-HD, Discovery [before TWCNYC's Discovery add]). Don't have all of RCN's frills, such as premiums, since I already have TWC's full "It's All Here" Road-Runner, all-premiums package.
Find I switch a lot between the HD sources to sample what's interesting. RCN might be 'better' with its Motorola 5100 converter, which doesn't have the faint 'fog' of my TWC SA3100HD that spoils black-level and contrast. TWC's Pioneer HD converter solves that, I understand, but I'm awaiting the upcoming SA8000HD (HD digital-video-recorder converter) from TWC, which better not have imaging fogging. (Some NYC areas already have access to a new RCN HD DVR/converter, as detailed at RCN.com.) My RCN basic service, needed for the HD tier, appears to be analog based rather than TWC's nearly all digital sourcing. With exceptions, I've found TWC's digital SD channels are better than its own or RCN's analog.
Haven't gotten into broadband speed; RCN has always claimed its got the best, although TWC started promoting a 50% boost in its speed a few months back. TWC has always been fast enough for me.
TWC is now claiming (see TWCNYC thread) that it has run out of bandwidth for new HD channels, and IMO, even though TWC has a good lineup, they've been fairly slow at adding new HDs compared to smaller systems around the country. Don't plan on keeping RCN indefinitely, just until any HD advantage of one over the other becomes clear. BTW, excluding the SA3100HD 'fog' problem, HD quality between the two seems similar. However, TWC is employing
rate-shaping technology to help conserve bandwidth, as outlined in this
article . Suspect you'd have to A-B with/without rate shaping, on a large screen, to see if image quality differences exist. I've done that several times comparing OTA CBS with TWC CBS, but the 2000HD/3100HD imaging fogging problem spoils the comparison. -- John
