All three ranges have 15k btu burners.

The Capital has all 4 at 15k,the BS 3 plus a simmer,and Berta has 15k plus a simmer plus two intermediate burners. IMO the growing consensus here at GW is these intermediate burners are the least effective. On 30" ranges you should have maybe one dedicated simmer and the rest power burners. There is nothing the intermediate burners can do that the simmer or power burner can not do.

The bigger advantage of the BS is the eveness of the heat.You can make an uneven burner cook better with good thick bottomed pots/pans. Or you can get the BS and start with good evenness and optionally make it better with better cookware.

The BS has a 15" heigh oven,the Capital 15" and the Berta 13". Some people think 14" is too low.

To answer you last question good power allows you to sear meat better,saute better,boil quicker,and recover temperatures better. Drop cold food into a pot of boiling water drops the temp of the water. High heat allows the pot to recover to that 212 or so degrees faster.Allowing more even cooking.

In short I would get the RCS.

BTW There used to be a lot of Berta owners post here not so much anymore. Not too many owners of that discontinued Capital Performance Series either. A few RCS owners.