...Not sure how expensive a new RV AC is to compare the two...
They seem to run $500-$800, plus the $300-$500 cost of a big enough inverter. The DC units are several times this cost, but also much more efficient; in the 1/3 less power usage range. Add another 15-20%% or so for inverter loses (if running off batteries), and we are about 50% savings in power. Then there is the savings because the DC models use the rotary variable speed compressor technology, saving the surge loads (and inefficiency) at startup. The rotary compressors also have the advantage that an oversized AC unit wouldn't be constantly cycling on and off, making for more consistent temperature in the RV, and much better humidity control.
It's a lot extra, but they do come with some real-world advantages.