I have several Remtronix antennas and like them all. I have the foldable tri-band 830 in BNC and SMA and they are both good antennas. Much better than stock on 700/800, better than stock on UHF and somewhat better on VHF. Either the 820S or 920S stay on my SDS100 all the time. Only for a real road trip would I hook up an external antenna to it; it does what I need with the Remtronix from inside just fine.
The 830 will definitely give you better all-round reception than the telescopic. Looks better, too.