I recently bought a brand new, in box Whistler XTR-130 off of ebay for $22 with free shipping (I love sniping on auctions). I decided to test it out so I took a nice little drive from CT to RI to visit the GF. There was a RI SP running off axis c/o K band on I 95 north in West Warwick area. He was well hid in a stand of trees in the center median. The XTR gave me at least 0.3-0.4 mile warning and I had plenty of time to slow from 75 to 55 PSL.
Overall I'm quite impressed by Whistler's most budget RD. The range is pretty good and I basically stole it for 22 dollars. The only dislike is the really weak volume. If I have my windows down and music up there is no way I would hear it alerting (and this one does not have the blinking periscope lights on top of it to get your attention).