Have both at 50 atm and cant decide 
i wanna have main but still switching 
My target is to play daily things and PvP
i wont pick stronger class, i just wanna hear Your opinions 
Well if you do not state what you are looking for, its tough to make you decide.
Overall striker will be more frustrating to play for sure.
He has no super armor ( practically ) and if anyone sneezes you are bound to get CCd while berskerer can make a build where every single ability is superarmor if I remember right, 5-6 bare minimum.
On the other side, striker is a racecar around the map and the berserker is a tank with a large cannon.
Per ability id say zerk hits harder on average but his abilities take a hot minute to cast ( superarmor tho so youre safe ) and they have a larger cooldown so he is less spammy between the 2.