I'm a new startup getting ready to open my doors and am expecting 3-7 signups per day (I've got lots of existing traffic from elsewhere). Which would be a better choice for me? Revecom or Ubersmith?

And what are the pros and cons?

Well.. only thing similar is they store clients information.
With Ubersmith... you need a seperate merchant account.

3-7 signups a day... you won't want RevEcom.. Go with a good Authorize.net account and Ubersmith. It's a great program.