+1 to relying on Tika for RSS parsing. If there's something missing that Nutch needs, we'll add it to Tika and roll it into 0.8.
There is also the parse-rss plugin in Nutch which is quite similar - what's the difference with the feed one again? Since the Tika parser would handle all sorts of feed formats why not simply rely on it?
I wrote parse-rss back in 2005, and used commons-feedparser from Kevin Burton and his crew. At the time it was well developed, and a little more flexible and easier for me to pick up than Rome. Since then however, its development has really become stagnant and it is no longer maintained.
In terms of real differences in terms of functionality, they are roughly equivalent so there isn't much difference. I would suggest we move forward with the feed plugin in Tika and roll it back in through Nutch.