I have an RS Discone that works great transmitting on 2 meters, vhf high, and UHF, but we swept it and it drops off fast lower than 2 meters--so as stated it would have a high swr for CB. Not so hot for anything higher either, but I have another ground plane 5/8 gain antenna for 700-800.
I have a 110 watt syntor that I use often on high band (154.xx) between denver & fort collins using the discone; SWR is good and it hasn't melted down yet.