I've been using Contact Form 7 on all my WordPress blogs for a long time. Contact Form 7 can manage multiple contact forms, plus you can customize the form and the mail contents flexibly with simple markup. The form supports Ajax-powered submitting, CAPTCHA, Akismet spam filtering and so on.
If you're like me, you'll have hundreds of accounts all over and you'll need to remember an equal number of usernames and passwords. Good security requires you do not keep the same password for all your accounts and so it would totally impossible for you to memorize all the passwords. This is where password managers come into play.
Using FeedBlitz or any third party service requires your visitors to move away from your site when they are subscribing or using that service. Google's Custom Search Engine as well as Adsense for Search ensured that visitors stayed on your site by embedding custom forms on pages of your site. Now, FeedBlitz has introduced Embedded Subscription Forms.