If your wondering how much you get and how much killing you need to do to get to that next rank this may give you an idea. found this in the forums.
Rank Points you get for alien kills and player kills
Aliens
-=[ Streuner ]=- 0.524
-=[ Lordakia ]=- 0.548
-=[ Devolarium ]=- 2.384
-=[ Mordon ]=- 1.192
-=[ Sibelon ]=- 3.268
-=[ Saimon ]=- 1.096
-=[ Sibelonit ]=- 1.692
-=[ Lordakium ]=- 4.536
-=[ Kristallin ]=- 1.884
-=[ Kristallon ]=- 7.072
-=[ StreuneR ]=- 1.192
-=[ Protegit ]=- 1.884
-=[ Cubikon ]=- 17.288
..::{ Boss Streuner }::.. 2.096
..::{ Boss Lordakia }::.. 2.192
..::{ Boss Mordon }::.. 4.768
..::{ Boss Saimon }::.. 4.384
..::{ Boss Devolarium }::.. 9.536
..::{ Boss Sibelonit }::.. 6.768
..::{ Boss Sibelon }::.. 13.072
..::{ Boss Lordakium }::... 18.144
..::{ Boss Kristallin }::.. 7.536
..::{ Boss Kristallon }::.. 28.288
..::{ Boss StreuneR }::.. 4.768
«¤( UberStreuner )¤» 4.192
«¤( UberLordakia )¤» 4.384
«¤( UberMordon )¤» 9.536
«¤( UberSaimon )¤» 8.768
«¤( UberDevolarium )¤» 19.072
«¤( UberSibelonit )¤» 13.536
«¤( UberSibelon )¤» 26.144
«¤( UberLordakium )¤» 36.288
«¤( UberKristallin )¤» 14.072
«¤( UberKristallon )¤» 56.576
«¤( UberStreuneR )¤» 9.536
Ships
Normal Phoenix 3.001
Battle map Phoenix 3.0015
4-5 and Homemap Phoenix 3.002
Normal Yamato 6.022
Battle map Yamato 6.033
4-5 and Homemap Yamato 6.044
Normal Leonov 12.044
Battle map Leonov 12.066
4-5 and Homemap Leonov 12.088
Normal Defcom 18.088
Battle map Defcom 18.132
4-5 and Homemap Defcom 18.176
Normal Liberator 24.176
Battle map Liberator 24.264
4-5 and Homemap Liberator 24.352
Normal Piranha 30.352
Battle map Piranha 30.528
4-5 and Homemap Piranha 30.704
Normal Nostromo 36.704
Battle map Nostromo 37.056
4-5 and Homemap Nostromo 37.408
Normal Vengeance 49.408
Battle map Vengeance 50.112
4-5 and Homemap Vengeance 50.816
Normal Bigboy 44.816
Battle map Bigboy 46.224
4-5 and Homemap Bigboy 47.632
Normal Goliath 65.632
Battle map Goliath 68.448
4-5 and Homemap Goliath 71.264