to be fair to Feedburner, they offer a variety of add-ins and
additional options besides basic feeds and statistics. The only one
of these I use is email subscriptions, and there are plenty of other
options for that specific one. However, if we're looking at just the
basic feed redirect and subscriber numbers, I'm not aware of any other
service that parses the feed hits like Feedburner does.
Now, the technical aspect of the subscriber numbers is pretty much
trivial. Parse a file of hits on the feed and decide if it is a
subscriber or not based on a set of rules about what made the hit - is
it a bot, a browser, or a reader. Those rules obviously take time to
develop and require monitoring as things change over time. But in the
scheme of things, it is not a resource-intensive service to offer.
Possibly because there are so many free or nearly free options out
there, it would be hard to make money by simply coming up with a
barebones service for say $3 or $5 per month that redirected feeds and
did good stats. You'd need thousands of subscribers to begin to make
it work.
I'll add that there is no easy way to "transfer" your subscribers
other than by announcing it and asking them to switch. People do it,
of course.
Finally, I'll say that I use this for podcasting and if my $5 per
month libsyn account had one more thing in their log file - detailed
hits to the feed - then I would abandon feedburner and simply
calculate subscriber numbers myself. Until they do, or something else
comes along, I'd be spending more time on technical stuff and less
time on content/promotion, and I don't want that.