Aliaz and Gateron Silent Brown are reputed to be very similar. They are both quieted Browns. Aliaz is probably quieter, and built to a higher standard. Aliaz 60 most closely resembles Browns, but some people use Aliaz 70 because they think the weight gives a greater tactile feedback.
Both of those switches are Browns, though, and not really an alternative to Zilent V1.
This leaves OUTEMU Silent Sky. These switches use some components that are good, and some that are iffy. You should order Silent Sky in pieces. At the very least, you will want to replace the spring, as it is pingy. You should lube the replacement spring, too. Definitely use the "tight tops," as they reduce the wobble of the switch. It's okay to use the Sky bottom housing, although I have heard that some people use actual MX Clears for that. The tactile stem is the best part of the Sky, and you can even put it in Ergo Clears.
So, Aliaz if you want quiet Browns, Silent Sky if you want quiet Ergo Clears. Do not use Silent Sky in stock form, though.
