I've tried all of the Remtronix antennas, including both 842 models. The 842 is a decent antenna, but it's not going to be a barn-burner, especially on VHF. Its best feature is the hinge, really. I prefer the 920s for UHF and 7/800 and keep it on my SDS100 most of the time; I use a ham dual-band antenna for VHF; a ¼-wave on VHF and a little gain on UHF.
The 842 is nice and compact, but it'll never compare to a full size one. I usually have one on my SDS200 for the local simulcast and weather channels. The 920 is probably the best UHF scanner antenna I have, and it's basically the equal of the 7/800 model on that band.
If you're primarily VHF/UHF, try a full length ham dual-bander. Local 800 will be strong enough to work, and your V/U reception will be as good as it can be.