Chinese air cooled spindles are very quiet, and don't blow a lot of air.
I've seen the argument about the spindle blowing chips around a LOT over the years. My opinion is that you should have a dust collector many times more powerful than the spindle cooling fan, which makes this point invalid. Without a decent dust collector, you'll have a room full of chips, and dust everywhere. A lot more than you'd think.
And with air cooled, you don't have to deal with any water cooling hassles.
I'd never pay $1700 for their spindle when I can get this for $300. But then I design and build my own machines.
https://www.ebay.com/itm/251263506939
(I own this VFD and two of these spindles)
The CNCRP spindle is probably louder than the round chinese spindles, as the square ones have different fans and better cooling. But a haven't heard anyone say they weren't happy with their cheap, round, chinese spindles.
I would not recommend a normal router. The bearings just won't last long.