There aren't hudmodels yet, so firstperson is a little 'odd'. Aside from missing the nice hudmodels themselves, this also means there is no model to calculate shot origins from, so they appear to start from the camera.
We should have hudmodels eventually. In the meantime we worked on making playing in thirdperson more enjoyable, with smoother camera movement, ability to control the camera behavior, etc. - see the 'help' menu in the game.
Performance
Overall, speed should be reasonable at this point, but you may experience slower performance than you expect - for example, in comparison to Sauerbraten. There are 2 reasons for this:
Little to no effort has been made to optimize our code for speed. There is a lot that can be done to make it faster, but our priority so far has been clear, stable code as opposed to fast.
Compared to Sauerbraten, our engine is much more flexible, so that does have some cost in the form of performance - but it should be small.
So, expect things to improve in future releases. In the meantime there are some things you can do yourself to improve speed, like change graphics quality settings, and make sure the logging level is set to WARNING (the default, unless you changed it).
You can also 'debug' performance issues using the built-in benchmarking tool. Edit the settings.cfg file in your home directory for Syntensity (by default, syntensity/client under the directory you put the client program in), and change it to have
[System] benchmarking = 1
This will then show you, in the console output, the amount of CPU time spent on physics and actions (actions are scripts run by entities) when you run the client program. Aside from these, the engine spends the rest of its time rendering. So if these two are fairly low, and performance is still poor, it may be that graphics settings are set too high.