Uniden R7 or R8 ?

I own an R7, and have an Escort 9600 in my daily driver. The Escort is suffering too many Ka alerts these days from bumper sensors et. al, and I'm thinking of replacing it. I probably only drive <7K a year. Should I buy another R7 and save maybe $250 less than the R8, or is the tech advancing where it's worth buying the R8 now so in 5 years it won't be worthless ? Or do we think the R7 will keep up ?