One VERY important thing to note about gas grills, though......they invariably have hot and cold spots. You will probably run into this problem with all grills.
Lastly, the cast iron smoker box works great. It'll take a while to get it heated enough to begin smoking, though.....
I think gas grills have moved backwards in this regard...the early models used a bed of lava rocks over the burner to even out the heat. At some point (and probably for cost savings) the rocks were replaced with sheet metal "tents" to diffuse the heat. They claim it's an improvement, but I have my doubts.
My inexpensive Char-Broil was purchased in 2001, and came with the sheet metal "flavorizer" bars. I hated it, the heat was incredibly uneven and every steak I cooked had well-done spots and rare spots. To get anything to cook evenly, I had to keep it moving constantly.
A few years later, I was cleaning the grill out and noticed the firebox had ledges in the casting to support a rock grate...probably a vestigial leftover from an earlier design. I tossed the heat tent assembly, bought an appropriately sized rock grate and lined it with those pyramid shaped ceramic briquettes. What a difference! It takes a few minutes longer to heat up, but now the heat is quite even...not perfect, but quite manageable. I've been very happy with the grill ever since.
Once a year, I toss those briquettes into a bucket full of oxyclean for an over night soak, rinse thoroughly, and return them to the grill. Half an hour or so on high, and they are clean, completely dry and ready to go.
My smoker box is actually made of steel, and cost $1.50 on Amazon several years ago. It heats up fast, and puts out copious amounts of smoke in just a few minutes. When I'm through (I dump the spent chips) which are now hardwood charcoal, into my bucket of lump.
