I replaced the OEM older version winegard with the Jack Digital HDTV Antenna as one of my first MODs. At first, I was going to add on the "Wingman" to help with the UHF-HD, but after seeing a demo at an RV show I decided to spend a little more on the Jack Digital. i actually bought mine through Amazon. (about hte same price as CW, but w/o shipping and tax)
I only have one piece of data to share, but the "before and after" test on the side of my house produced ~ 11 more channels using the Jack Digital Antenna. btw..it was a very easy unstall.
I also use the King Control Dig TV Finder
(Amazon link) which helps locate th strongest digital signal prior to doing a channel scan
Just rotate the antenna and peak the signal strength. Works great...especially in fringe areas
Hope this helps!