I have the V1, STI-r Plus and 9500ci in all my vehicles.
STI-R plus works best. However, alerts are hard to hear compared to the V1 and 9500ci.
9500Ci is a close second if not identical to the STiR STI-r wins because I can lock out frequencies to reduce possible falses.
V1 has failed me twice this past year in the same area. It's the current firmware. The only reason I keep the V1 is for portability.
That said, the STi-r and 9500ci are both very expensive units. You can buy 3-4 V1's for the price of either. Range IS better on the 9500/stir and I find my reaction time is better on them as well. Due to the GPS lockout, I know a signal is really a radar signal. With the V1, I have to look at the data and make a decision, which slows my reaction at least 1/2 second.
Window mount and budget, the V1 wins hands down. ~400. With no budget, take a serious look at the 9500ci and the STi-R. They can be had online for about the same money. Plan on most of the day for an install. I have 8 hours in mine and I'm not finished. Unit cost was about ~$1300 Then I put the display in the mirror and wired a mute button to one of the unused factory switches below the AC panel.
I'll be adding HP Laser Interceptors to the car soon.
I have no experience with the Redline.