I’ve run both. The dewalt sounds like a banshee that just racked itself on it’s bicycle, the 500w spindle I have is waaaay quieter. I’ve done aluminum on both. If you are running a shop vac at the same time, it doesn’t matter, the vac is just as loud. Once you start cutting it’s also pretty loud, but I’ve run mine with the vac off without earpro for short runs and it didn’t hurt my ears. Bear in mind I used to work around running military jet aircraft, so my opinion on what’s loud is subject to how bad my ears are already ringing that day. The only thing I don’t like about the spindle is how far the collet holder sticks out. When it comes down to it, the spindle is just a motor with a collet holder bolted to the shaft, so it adds a couple inches in length over the dewalt. The fancier spindles have hollow shafts, so the end mills can go up through them, so they’re shorter. I got mine from Inventables.