yes it is a good coin to invest on more personally I am not encouraged to invest in it because the value is already high and the possibility that it will show significant rise in the future maybe very low create a new coin that is coming up.
Yes, I think we must invest when the prices go down, but problems arises when the coin fluctuates more after we invest. This is why cryptocurrency trading could be really risky. However, we can try to minimize the loss if we sell our coins if we observe the downfall of the market. I always sell my coins before the market falls further.