Digital and analog have nothing to do with it. The RS 800MHz antenna will improve your 800MHz reception regardless of the type of modulation used..If your listening is based on 800mhz digital channels, Then Yes, that is a excellent antenna, if your listening to analog channels then that antenna is not what you want.
The R/S 800 MHz antenna definitely would not be as good as the stock on Vhf-low (30-50MHz). Not as good on Vhf-high (say 140->170MHz), but I would not call it deaf. I can still generally get all of the reasonably expected agencies in the area, though I do lose some of the weakest, or fringe, transmitters (not unexpected, and they are covered by a different scanner/antenna pair). Uhf (~450MHz) also comes in well, no noticeable loss on the systems I monitor. Just remember that there is not a perfect antenna for all bands at the same time.
i have the antenna on PRO-163 with a right angle and it picks up the 140 and 150 band pretty good, i've noticed that whenever i have my 163 in the car and i have the 800mhz antenna on it, it works as well as a mobile antenna,while were moving
in a word... "yes". If I am trying to listen to either range you indicate... the stock antenna tends to do better, imho.