Personally, I vastly prefer both Dunsany and Lovecraft to CAS. CAS has some really great concepts and atmospheres but tends to not explore them as satisfactorily (to me) as Dunsany or Lovecraft. Also, it seems strange to say this, but I honestly think these Zothique stories were more depressing than most of Lovecraft. So my preference for this type of fiction would be Dunsany > Lovecraft > Howard > CAS.
It should probably come as no surprise that I think CAS explores his ideas quite satisfactorily, with some exceptions. I don't find any of this stuff the least bit depressing. That could be because I'm something of an outsider, socially speaking (I choose to not participate in American society much, preferring to observe it from afar). The CAS stuff in particular seems almost deliberately designed to appeal to misfits, cynics, and oddballs such as myself. I admit to having a slight (but healthy) misanthropic streak in my makeup.