Can’t comment on either of the models you linked to, but my outdoor gas grill uses a vertically mounted (on the back wall) infrared “burner” for rotisserie cooking. We’ve used it twice this year and it produces awesome chicken. It takes about 1 – 1.5 hrs to cook a whole chicken, but the result is very juicy bird with a real nice color on the outside. I will say though that out of the two times, once I ended up having to augment the infrared burner with the traditional burners down below at the very end just to make sure the bird got up to 180F internally. I have a nice digital probe thermometer and Mrs. nrd and I are somewhat fanatical about cooking chicken, so, one way or another that bird was going to get up to 180 before it got off the spit.
However, like I said, this is only a vertical mount rotisserie unit, so I can’t comment on the grills you linked to.