Honestly the best viewer for second life has changed for me over time. Right now it is Alchemy viewer from https://www.alchemyviewer.org/. It is pretty smooth and RLV functions work so well.
Before this I used to use Catznip, from https://get.catznip.com/. It has pretty good load up time and is very less likely to crash than the official second life viewer. This is my personal experience.
I personally never liked the official viewer or the Firestorm ones. Mainly because of stability issues. They never felt stable. They keep crashing and voice never seems to work on them. So if you are facing frequent crashes or caught in teleport limbos or the voice doesn't work, it's time to ditch these viewers. Go for the first or the second one I mentioned.
That's all for today. Let me know which viewer you use in the comments section below.
