I would definitely recommend creating a custom feature. That way, your form will fully integrate into the site, and you can easily reuse the form on multiple pages as well.
I also need to give a plug for the Form Wizard Pro product if you need to create even a couple of custom forms. It saves data into the database and offers several ways to pull that data back out for analysis. We bought it and it works great. It's very reasonably priced, and best of all, the proceeds are going directly to help keep the mojoPortal project moving along.