OK, I've finally found a review of the Whistler 3450 HERE. Some of the most important information is probably in this section...
"The promised performance enhancements were evident when we measured the Whistler's radar detection range. At the Straightaway/Hills test site, in X-band Highway it was tied with the BEL and was within nine percent of the BEL's range on K band. In X-band City mode its 27,648-foot range far eclipsed the BEL's 10,135 feet. On Ka band it was Whistler: 14,635 feet, BEL: 27,950. At the fiendishly difficult Curve Test site it trailed the BEL by about 1,000 feet on X and K bands and about half again that much on Ka band, a very creditable performance. And it was quiet in town, particularly when placed in City 2 mode to silence the nuisance of automatic door openers.
When we squared off against the laser, its windshield-mounted module was unable to detect the laser's narrow beam at our standard 1,000-foot target range. So we relocated the module closer to the dash and it came alive, delivering an impressive 81-inch average of field of view, no doubt the payoff of the module's panoramic array of three detector diodes."
However, I'm not sure how that compares with the Escort 8500, I've never seen it's stats.
My main question on the radar above though, and any remote mount, which is why I posted this in "general" and not "Whistler"; with a remote mount unit, I've seen reference to rear antennas; does this mean that this (and other) remote mount units will not detect a rear threat? If that's the case, this unit, nor any other without rear antennas, aren't even worth the time if there's not a way to detect a rear threat.