RAM's launcher can revolve around and adjust the azimuth angle, thus fires the missile towards the target.Bro here my 50 cent: Sea Ceptor is launched vertically and gives 360 degree cover whereas RAM can't.
Sea Ceptor also uses soft launch which has own pros.
While sea ceptor spends time to accelarate vertically and then maneuver towards the target and adjust the altitude.
One is better for very short distance and very low altitudes while latter is better at a greater distance.
Like CAMM would perform better than ESSM below 5 kms while ESSM would be better distances above 10 kms
The distances are entirely fictitious