Forced Air Register Airflow Direction?

I just installed several new registers that directs heat or a/c through the *sides* (or angled at 90 degrees) out of the registers, as opposed to the older registers that I replaced, which shot the air straight out.
I'm really wondering if I'm making the system work less efficiently now that the air shoots sideways from lower walls, as opposed to straight out into a room.
Note that the louvers flap up and down on the new, just as the old. It's just the outside shell that has fixed louvers that point sideways.
What is the advantage/disadvantage and purpose of each style? Is there a site that you know of that explains the various styles of registers and their uses?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.