We have the Jensen "saucer" antenna and it suxs.
I am an antenna "nut", I have studied antennas, designed antenna, taken advanced classes in antenna design (College 400 and 500 series) and published on antennas.
When we got the rig and I started testing I was appalled. At home, with the new RV in the same location as the old RV (which has a Winngard Batwing) I got roughly 1/4 of the number of "stations".
So I disconnected the antenna and connected random chunk of wire to the coax on the roof and got more stations.
I then bought a "disc" antenna from Radio Shack and connected that. The new antenna was at roughly 6 ft high (vrs 13 ft for the one on the RV). I got the same number of "stations" as with the old RV.
I couldn't install the regular batwing as the crank would be higher then I could reach.
But yes, IMO almost any antenna will would better.