The oval shape of the Primo XL sets it apart. Of course that all depends on your budget. If you are tight for money, the UDS + chargriller option is not a bad way to go. I have a Primo and big daddy smoker (UDS). When I am smoking low and slow, I use the UDS. The Primo is used more for grilling these days, but works very well for smoking too.
Primo Oval XL, BPS drum, Weber gasser