The Milwaukee portable is the best battery/car compressor I've used. That includes its DeWalt competitor, some yellow pistol grip cigar lighter one that might be a Stanley or something and a 20 year old China cig lighter plug in no name called "Truck Air". I have never used an on-board like ARB or Viair.
I like it so much that I just bought a second one like a few others seem to be doing. See the post #23 near the top of page 2 of this thread for the Project Farm inflator test;
https://www.fordtremor.com/threads/milwakee-m18-18v-cordless-tire-inflator-2848.17500/post-360685
I'm now a mixed household between Yellow and Red, buying what seems best between the two for any given tool that I decide I need or if replacing so the extra M18 batteries are part of the attraction. I also have battery adapters to go in both directions which is handy.