Which is better to write: Ω or Omega_Total ?

Hi Art_Deco ( a.k.a. Duckie ), www.Cotse.NET/users/jeffrelf/W.PNG
You told me: You're a kook, an underscore abuser.

Following the Modula-2/C++ tradition that I was raised on
( Modula-2 since the start of 1982, on the Lilith computer ),
I used indentifiers like Omega_Total in the W.PNG above
instead of the Ω characters found in the .PDF it references:
http://www.RSSD.ESA.INT/SA/PLANCK/do...(2005)1_V2.pdf

Which is better to write: Ω or Omega_Total ?
Which is more editable ? searchable ? readable ? assiduous ? you tell me.