We now have SSA enabled on the Le Tigre Release Candidate channels. For a list of regions running SSA see my article: Le Tigre Regions List. So, what is it like? Well, my opinion is it really depends somewhat on the viewer you are using, but generally better.

So, far my best experience has been with the Production release of the SL Viewer version 3.6.1-278007. I’ve had some crashing as I tp from SSA to non-SSA regions. But, otherwise, it is the best I’ve seen.
The Beta version of the SL viewer is another story. It is the worst of those I tried. I expect that to change. It is called beta for a reason.
