Some are faster than others... I have an orange/red one that grows very fast (so fast I got it for free because the person had too much). I have an purple cap that grows so slow... I have a candy apple green that grows inbetween...
The only thing about having them in a small tank is that for SPS corals you need to have perfect tank conditions. You would have to stay on top of top of and dosing and the smaller the tank the more drastic the changes are in it.
As far as stinging I would say it depends on what it's going against...