I agree with battlefield in comparison with BO3. Now if you had said B01 or even 2 the scale would still lean toward Battlefield, but I would enjoy either one. Loved black ops 1 and then 2 was a decent sequel.
Battlefield does very well with their server management as well which is something the COD devs haven't really mastered. I think Battlefield could more realistically handle the bandwidth and deliver a smoother experience with way more detail and much larger maps. COD needs dedicated servers for everyone. I also think that Battlefield has more variety in weapons and classes and that 18 vs 18 in COD would get boring. Personal Opinion.