because its what he wants to do.

>why dont you learn more common php or asp.net instead of cold fusion?
Because he already knows PHP and ASP.NET?
Because his employer requires him to learn ColdFusion?
Because there aren't as many ColdFusion programmers and he could make bank by becoming one?
Because he's simply interested in it and it's none of your damn business?

>so it is crucial to know your options..
You assume too much. smith2009 simply said he's learning ColdFusion. You know exactly nothing about his reasons for doing so, or his knowledge about alternatives.

>one of my classmates recently said that - according to what he
>heard- writing one line of coldfusion is the same thing written with
>100 lines of c#, remembering that kind of fallacy
The only fallacy is you using hearsay ("I heard it from my classmate who heard it from somewhere") as fact.

>it is better to have a good comparison among the options before starting.
That's a fabulous idea. I strongly suggest that you follow that advice, since clearly you lack the experience necessary to compare ColdFusion to anything, much less recommend alternatives to it.