Yes, pros and cons to the ego.
Ego is an excellent driver for self-improvement and lifestyle enhancement.
Left unchecked it can also get quite poisonous, especially if it feels wronged, or veers too far into 'win at all costs' territory.
The Eastern religions have long focused on moving past ego to attain wisdom and inner peace. Western philosophy has often centered around control of the ego as well.
If you want to experience why ego is not an unalloyed good, 10 minutes of meditation will do the trick. Sit in a quiet room, close your eyes, and with each breath in, picture a thought, and with each breath out, release it. The thoughts streaming through your mind are ego. You will notice as you pay attention to them they're attached to feelings of stress, anger, resentment, acquisitiveness, and other such things. Once you've released most of them, you will still be you, but you will be at peace, your mind will be clear, and all the negative emotions that come attached with ego will be gone. What you feel is the self, detached from ego. It's a nice feeling.
Ego is a tool, really, used for navigating the world. So long as it's in service to your self, it's useful.
Ego has a tendency of overriding the self, and thinking itself the self, however. At which point you start to get more of the negative effects -- bad emotions, win-lose situations, burnt bridges with people you used to have good relationships with, and so on.
You can't exist without ego, unless you are a monk, removed from the world. Even then, you will still have some.
But it is good to be aware of its limitations, and do one's best to keep the ego in service to the self, rather than let the ego subsume the self in its hurry for a degree of emotional satisfaction it can never long attain.