Pros
make you prepare to face the worst circumstances in life!
Cons
except mobile carrier network, rest of their products (specially enterprise products) are bad and if you are unlucky and working on those products will make your market value to go on toss. Because no one in market use their products or even know about it (except africa lol). So if you are working on those products that no one uses in main stream, your experience will not count much and will not help in getting job again. For eg: They have their own UC solution, routers, switches etc. And if you are working on those products as a fresher, when you'll move out no one will consider ur exp as they will ask questions related to cisco/ juniper etc and no one really cares abt how huawei device works as no one uses it except few unlucky tribal people in africa and small countries in world. So think twice before making a decision to join huawei.