I've been a SL user for over 4 years. I use SL for both work and play. Mostly, I script.
I love change, when it's for a good reason. I love trying new things. But...
In my opinion, LL Viewers 2.1, 2.2, and 2.3 just plain suck. I despise them, and only use 2.3 only for testing, and I hate doing even that. Mostly I use a previous (April 2010) version of SnowGlobe, which rocks.
Kirsten's Viewer is a bit of an improvement over LL's 2.3, if you simply must have something all fancy looking. And it's more stable than 2.3, with some bonus features.
If LL ever _forces_ me to use 2.x crap, I'll probably quit SL and move to OpenSim, where I already am anyways. Out of all the good, bad, and ugly changes in SL over the past 2 years, 2.x is by far the WORST.
Please, LL, drop the 2.x project. I and 96% of my SL friends despise it and avoid it like the plague.
And, btw, Display Names... completely useless feature, in my opinion. I don't need even more float text on the screen, or identity confusion. I'd rather have better search and all the other fixes we've been asking for...for years.
My perfect viewer would be SnowGlobe (previous version) with the new tattoo layers feature added.