hi good question,
I have seen this question asked a few times in the past, and I also use RSS on most of my personal websites and I have never really had any problems with it. In my opinion RSS is good for pinging new content to SE's and also to 3rd party sites who take your feed.
Sure enough if the client is worried and the content is more so static on the website then I would not opt for RSS.
Yet if the client has a website where they are promoting alot of content on a daily basis and weekly basis pretty much all the time then it is advisable to ass RSS in my opinion.
A good answer to this question can also be found here:
http://forums.searchenginewatch.com/showpost.php?p=96875&postcount=6
and also here:
http://www.google.com/support/forum/p/Webmasters/thread?tid=688304ae0edc7faf&hl=en
