i dont drive without, saved my a$$ plenty. Read all you can, I found info thru search and clips from magazine tests online. I use Escort and love it,
i am on my second. probably 6-7 yrs old now and going to replace just because there is so much advancement in radar.
All should work well, but you will be surprised in how the so called experts rate them, and where you drive (i.e. hills, town, Fwy....). V1 is good but pricey.