Yeah, I don't use Smart Mailboxes - never figured out what good they were either.
Just need regular Mailbox and then create rules.
I imagine the rules will work with Smart Mailboxes also.
Easy way, after you create a Mailbox where you want something to go - instead of your inbox...
Highlight an email that you want to go there.
Open up Preferences - Rules - Add Rule - Give it a title, I have one called Misc Junk
I name the rules the same as the mailbox I want them to go into.
The first box - I leave as "any"
Then in the conditions box use "From" and "Contains"
If you had that email highlighted - it will automatically fill in the 3rd box.
Here's a pic of my Misc Junk
You'll notice I shorten the name down - takes care of some of these sites that like to use multiple domains to send you mail without the need to make a rule for each.
When you're done at the bottom, make sure you put in what/where you want it to do with that email.
And it's a little confusing - but just click the plus sign next to any existing line to open a new line to add other senders to this rule.