we have a rooftop Trav'Ler on the DISH Network and love it.
pros are ease of setup and automatic lock onto the satellites. one button does it all. while I'm setting up camp I power up the Trav'ler and by the time I'm done it's up and locked onto the 3-western arc satellites. same with when we break camp. I power off the Trav'Ler and before I'm done the antenna is down and stored.
cons are the inability to move the antenna if trees or other obstacles are in the way. we deal with this by carefully choosing the parks we stay in...looking at them on Google Earth and talking with campground management in advance.
AFAIK the Trav'Ler (rooftop and portable models) are the only automatic, HD capable antennas for DISH and maybe DirecTV but I could be wrong on that. I didn't need to do a lot of research as I did not want to fool with a portable antenna/tripod even one that was automatic. didn't want to lose storage space either.
good luck.