On the whole, I'd suggest steering clear of table-less forms. We still offer that as an option, but we've been debating deprecating that as a feature, as it doesn't get much testing, and it's becoming harder to provide support for in the code.
It's not something we're going to just drop overnight, but you may find life is a little easier if you use a table. And you may actually find it useful, even for a simple form that sends an email, for analytic purposes. If not, you can always set up a really simple scheduled task which runs once a day and truncates the table, to stop cruft accumulation.
-- hugh