Also in response to Brick's request for more cheapie reivews:
The Cobra ESD-9870
This was the 3rd detector I owned. I bought it after returning a ESD-9210 becaues of all the POP mode hype.
Audio- Tones were distinct, in fact pretty similar to the Bel stuff. While they would almost get loud enough, it was somewhat distorted on high volumes. (remember I have a whole different definition of loud than most people, i'm sure almost everyone would find it adequate). It's louder than the 9210, but not as clear.
The display is so-so as well. It had a nice text display with a good menu system, but bright sunlight caused it to be pretty hard to read, since it was a yellow display.
Mount- Didn't ever rattle, but wasn't all that stable. Fell off now and then. Here's a pic-
The little rubber feet kept it from rattling, but the detector set back off the window a ways.
The 9870 was a long unit, so it did wobble around some.
Cord needed to be longer. It was a coiled cord, and really, had it been a standard cord it would have been long enough, but it didn't seem to stretch much without pulling the unit off the window.
K-Band performance was pretty good for a cheapie. Even from the rear it was pretty good. It might have had a little trouble detecting distant instant-on.
Ka was pretty good in town, but on the highway, the warning might not have been enough in some situations. While I was never able to verify it myself, supposedly the range to the rear on Ka with the 9870 is horrible.
Laser was nothing special. Even mounted low, I went right through two laser traps with not so much as a beep, but they were both close range, so I don't know that anything would have alerted.
Pop mode falsing was simply unbearable, and when POP was enabled, standard Ka falsing went way up as well. It was un-usable with POP on, no two ways about it.
Died after a few months, but it was left in the sun too much and fell off the window too many times. Cobra did send me a brand-new XRS-9700, so can't complain.