As much as I love Assembly Language, using C to program a microcontroller seems like a real time-saver. Although, of course, with C you do lose some efficiency when compared to programming at the lowest level...
let us say that the time to develop in C will be 200 Hours
let us say that the time to develop in assembler will be 400 Hours
let us say that a developer hour cost (salary, medical, vacation, office space, administration, ...) $100
let us say that the choice is between an 8k LPC935 @$1.74 programmed in assembler and a 16k LPC936 @$2.22 programmed in C

this give a price difference of $0.48
the added cost programming in assembler is $20,000
$20,000/$0.48 ~ 42,000

thus if you sell more than 42,000 units there MAY be an advantage using assembler.

Of course, if you are Richard, it will be faster doen in assembler, but that is the exception

Erik