I need to choose an online email newsletter program. Constant Comment VS. YMLP?

For a small business that does a weekly email blast of 150 to 200 email addresses the best of the sites I've found so far are Constant Comment and Your Mail List Provider. Can anyone give me pros and cons for each of those? Are there other services you would recommend? There must be image capabilities and flexibility of colors, fonts, templates, tables, etc,.

"... There must be image capabilities and flexibility of colors, fonts, templates, tables, etc,." You're apparently looking for mail services that will send HTML formatted messages. These days, there are plenty of those. But as far as I know, Constant Comment is a brand of orange flavored tea, and Constant Contact is a mail list service: http://search.constantcontact.com/home.j...
As is YMLP: http://www.yourmailinglistprovider.com/f...

As for pros and cons, first, you should also know that many people still filter all HTML formatted messages straight to the trash as probable spam. I do. If you want me to read an email you've written, send plaintext. If you want me to look at pictures, or formatted Web pages, make your case in plaintext, and include a link to a Web page you want me to view.

If you employ mail delivery services that send HTML mail, expect regular delivery problems, as these services are put on Real Time Blacklists http://www.mxtoolbox.com/blacklists.aspx... , and get themselves off such lists, and are put back on, and get off, and go on, and get off.... ad infinitum. Noob spammers love those services. Serious spammers, of course, get bot-nets to do their dirty work. For your own information, see the advice at mail-list.com (a plaintext only mail list service) about these issues: http://www.mail-list.com/

That said, Sparklist might be what you want: http://www.sparklist.com/services/campai...