I use Feedblitz to send email updates for my blogs. I've been using it for years, and I see no reason to switch to another service (yes, I've looked into other rss to email newsletter services).
Here are some of the things I like about Feedblitz:
*You get to choose when and how often your newletter goes out.
I don't see the point in sending out daily emails with updates--those who want daily updates will usually just ad your feed to their google page (or whatever option they use to follow feeds).
Feedburner may have this option, but I never could figure out how to set up anything other than daily emails.
*You can send out "newsflash"--a mass email to all of your subscribers.
Occasionally I'll want to send an announcement to all of my subscribers. I don't do this very often (people don't like to have their email boxes cluttered), but this feature is really helpful when you need to send a message to all your subscribers.
*You can manually ad subscribers.
I have the opportunity to meet thousands of new people every year through speaking engagements. Sometimes I collect the email addresses of those who are interested in following my blog. Feedblitz gives you the option of manually adding/importing addresses.
*It's pretty simple to set up.
You just create an account and ad the code to your blog. You'll end up with a nifty little form on your blog where folks can enter their email address.
*It's automatic.
Once you've set it up, Feedblitz will automatically send out emails with your latest posts according to the schedule you set.
These are just a few of the reasons I use Feedblitz.