Depends if they are made by Huawei
I guess it depends on what you mean secure. Neither can really be attacked from someone on the internet since you can't generally configure routers from the internet unless they have a special option. Since you don't generally get a public address on a cell router it might be a extra level since nobody can even reach the private addresses assigned.
Now if you mean bugs that is hard to say. Its not like either have a lot but cell routers are more complex but they also have the cell companies putting out patches to protect their network.