I've got an ash/maple Warmoth with 60's spacing, and an Alder/RW Regenerate Guitar Works with 70's spacing. Identical pickups in both, but some minor differences in hardware, and the Warmoth has steel rods, while the RGW has carbon fiber rods.
Without a doubt, the RGW is far more growly, but not as bright. The Warmoth is smoother and more scooped. The bottom end is about the same, but the Warmoth has a brighter top end and scooped midrange. The RGW articulates very well and has a ton of growl, but the top is just a little tamer. Despite identical pickups, though placed differently, they are quite different sounding instruments.
For straight up rock, blues, country, etc, the RGW is the right bass. It's a thick, meaty sound that's more like a P-bass. I also love the bridge pickup solo'd for some jazz. But for R&B, Reggae, slap, fusion, etc, the Warmoth is my go-to choice.
I'm sure results will vary with different instruments, but I think the 70's spacing gives noticeably more growl, while the 60's spacing is generally smoother.