I think it depends on your level of investment expertise. I make a lot more money on the money invested vs what I lose financing. I can make more money in the stock market over time than even rates back to the 90s. I'll also take the tax deduction. YMMV.
On the other hand, I avoid buying new vehicles which is the opposite of some of you who pay cash. After years of trading in pretty good vehicles/boats/RVs, etc, I came to realize that other people probably are too. So, I buy used and let them take the depreciation.
It does take some research, but there is nothing to guarantee that a new vehicle/RV will stay together past the warranty. Also, if you've been listening/reading, you'll know that most RV/vehicle problems are usually discovered in the first year or two. If you feel lucky, go for it. I will go used from now on. You guys can take the depreciation and hope for luck that you bought a good one ... pay off your houses.
Do what you are comfortable with ...