I am an MCP (not that it means much)....I am trained to explain PC concepts in plain non-tech speak....to people who are not technically minded. For some services that is not worth trying.....for others it's a piece of cake, RSS is one of the latter. I'd suggest that if you can't explain something as simple as that in plain speak then you really need to look at yourself.
How difficult is Sage for Firefox? All you do is click the Sage icon which brings up sage in the sidebar, and when you're on a site you want to subscribe to click "search".....it'll find the feed, just say "yes". Most RSS readers are pretty close to this simplicity....it's not like your showing them how to edit the registry.
As things are, by opting for an email only option you are screwing your subscribers when they don't need to be....you are setting them up for an unnecessarily painful start to the internet. One which they may well resent you for down the line.
You said many experienced net users would use their own readers anyway, I agree.....that leaves the newbies (who you are playing the role of teacher to) who must have done the same research and found that both feedburner and google are trustworthy companies right? Or are you encouraging them to just take the word of a website owner that everything is fine......again, setting them up to be screwed.
Sorry if this appears to be confrontational, but where I took issue with it was that you're harvesting for no reason. You're kinda in the role of teacher to some...and you're taking an easy way out which is VERY detrimental to the people you're teaching.
If a student does not learn properly......whose fault is it? The student for not learning right or the teacher for not teaching right? You've probably already guessed my answer to that question.