Preventing Form Spam in cf_sebForm
I use cf_sebForm for all of my contact forms. Form spam is a constant problem for those forms. So, I set up a generic way to do filtering in those forms and wrote both cf_sebForm and SpamFilter.cfc to follow the same guidelines.
Good question. I definitely wouldn't say that one approach is better than the other - they are just different.
Both SpamFilter.cfc and CFFormProtect aim to prevent spam with no impact to the user or disruption of accessibility.
CFFormProtect takes a combination approach - looking first at behaviors and then looking at the content of the message (including the use of Akistmet). All review that I have heard say that this is highly effective.
SpamFilter.cfc only uses content checking and doesn't use Akismet, because Akismet is only free for personal use, not business use.
The primary difference is that CFFormProtect is specific to forms and requires code in the form itself and has dependencies to JavaScript files. SpamFilter.cfc is more of a general use filter and doesn't require any JavaScript or code on the form itself. You can actually pass any structure into SpamFilter.cfc to have it check it for spam.
SpamFilter.cfc also allows you to update the words and regular expressions that it uses to define spams.
My preference for SpamFilter.cfc is that it is non-invasive (no need to touch much code to implement), it works just as well against manual spam as automated spam, and I can implement it just the spam on personal or business sites.