No opinion on the specific issue at hand, but wouldn't you eventually want to take the winning system of laws and implement it on federal level? Or would you expect better performing systems to naturally spread over? Are there any examples of that actually happening?
I think it is not state spread vs. federal, but more like state spread -> federal. Disclaimer: talking about the US.
For something simple that can stand on its own, that was what we saw with gay marriage and, I personally believe, what we will see with cannabis legalization.
For something as complex and interconnected as property taxes, I don't think it will be that easy to convert it to federal, so state spread is what we can hope for in the near future. An example of a similar issue is income taxing, where we ended up with a two-tiered solution: one federal (same for every state) + one state (differs for each state, with some having none at all).
You're assuming there'd be a winning system, that's a bad assumption, different systems would be acceptable to different sets of people. There isn't one right answer, there are many and people will gravitate to the ones they like. It's good that states can compete for citizens with each other.
