That's an interesting (and worthwhile) question, even though it's been asked often.
HubPages has a...I guess you could call it a "Pass/Fail" grading system that essentially says either, "We believe this is a really solid piece of writing," or, "Uh...we not impressed!".
If it's Featured, the HP spiel is that they make it more visible to other Hubbers (which is true) AND that it's "visible to search engines" (at which I snort derisively).
That is, HP may well be notifying Google either to "pay attention to this one" or "don't bother"...but in my experience, the search engines make up their own minds. I've had non-featured Hubs that ranked very well in Google despite not being Featured--which is a statement you won't hear from many. In fact, I've only heard it from me.
However, I do know this for a fact: Most of my more recent Hubs get Featured within the first 24 hour "company review", but some don't. In recent weeks, there were two that did not--which really ticked me off, because both of them were (in my opinion) great pieces. Political Hubs I don't even check, but these were on other topics.
But get this: I didn't back off, didn't freak out and try to rewrite anything. In fact, in the first case, I made sure to have it come up FIRST in my Profile scroll.
Within days, BOTH of the "non-Featured" Hubs became Featured. I presume because they were getting traffic and praise comments from readers, but have no way to know for sure.
ONE THING: In your Edit Profile page, you may want to check to be sure the box is checked (or unchecked, whichever way that goes, I forget) so that ALL of your Hubs SHOW to the public, and NOT just your Featured Hubs. I've got several hundred Featured Hubs, including nearly all of the newest ones, but more than a thousand NOT Featured...and I wouldn't want them "hidden" from visitors to my HP profile.
Hope this helps.