As you can see in this BBQ smoker the doors open left and right.  This eliminates the need to lift lids which makes it safer and easier to handle

Because this BBQ smoker is rectangular we build the grill section around 36" tall vs 30" with a cylinder. This gives you more clearance between the shelves and between the top shelf and the top of the grill section. Another benefit of this smoker is that all 3 grates have the same width.  This gives you more cooking area compared to a cylindrical section because the cylinder becomes narrower as we move to the top.

The cooking grate of this slide out BBQ grill cranks up and down.  It can be placed in any position and allow for the lid to be closed.  This is a terrific feature if you are grilling some thick cuts or chicken

 

While you can control the air intake from the front of the grill it is very easy to tend to the fire from the back