I'm not sure what you mean by "stronger". Does Pikachu have better stats? Not that I know of.
But is Pikachu good? Yes, relatively. It's fast with decent moves.For generation one, there's not too much you can put into in terms of team building and all. Having a fast Electric mouse is helpful against tougher trainers some, but that depends on the rest of your team.
Although there's not too much variety in Yellow, if you feel another Pokemon is stronger, then you can store it without guilt. It's good, not great.