The reason why most people dont like it is because they are a lower rank than others. For example im level 15 most people in my game are 10 and lower and there is a big difference to the levels. also you have to earn attatchments or upgrades.I like the defenders side because of the Ak-74's(I dont know why i just prefer them). So if i was you just get used to one gun that you like and use it and get all the upgrades, and also try to unlock the SV98 and upgrades for that and the Shot gun( it helps alot). i have all the upgrades on the AK-74's and i feel that when you get to the thermal site on any gun USE IT!!!!
Hope this helped please THANK or REP+