Pros
Engineers at Huawei are world class builders and are very open and passionate about new technical ideas. Cutting edge technology is easy to get experience with if you have ambition and a curious mind. You can travel to China and many other countries, and learn every step of the way. Huawei's pay is higher than market rates, typically significantly so. US workers perform advanced development and do not undergo the same treadmill-like lifestyle found in many other software shops. In short, it can be a unique opportunity for someone with an open mind, and for those who like to invent.
Cons
The company has been singled out by the US government as a bad actor, although no evidence of "backdoors" has been produced as of yet. This stigma is annoying. People used to a highly organized "scrum" culture, or who are not self motivated, will probably be unhappy. People who cannot work well with other cultures probably would be a bad fit.