We rank the six latest Type Ia supernova ( SnIa ) datasets ( Constitution ( C ) , Union ( U ) , ESSENCE ( Davis ) ( E ) , Gold06 ( G ) , SNLS 1yr ( S ) and SDSS-II ( D ) ) in the context of the Chevalier-Polarski-Linder ( CPL ) parametrization w ( a ) = w _ { 0 } + w _ { 1 } ( 1 - a ) , according to their Figure of Merit ( FoM ) , their consistency with the cosmological constant ( \Lambda CDM ) , their consistency with standard rulers ( Cosmic Microwave Background ( CMB ) and Baryon Acoustic Oscillations ( BAO ) ) and their mutual consistency . We find a significant improvement of the FoM ( defined as the inverse area of the 95.4 \% parameter contour ) with the number of SnIa of these datasets ( ( C ) highest FoM , ( U ) , ( G ) , ( D ) , ( E ) , ( S ) lowest FoM ) . Standard rulers ( CMB+BAO ) have a better FoM by about a factor of 3 , compared to the highest FoM SnIa dataset ( C ) . We also find that the ranking sequence based on consistency with \Lambda CDM is identical with the corresponding ranking based on consistency with standard rulers ( ( S ) most consistent , ( D ) , ( C ) , ( E ) , ( U ) , ( G ) least consistent ) . The ranking sequence of the datasets however changes when we consider the consistency with an expansion history corresponding to evolving dark energy ( w _ { 0 } ,w _ { 1 } ) = ( -1.4 , 2 ) crossing the phantom divide line w = -1 ( it is practically reversed to ( G ) , ( U ) , ( E ) , ( S ) , ( D ) , ( C ) ) . The SALT2 and MLCS2k2 fitters are also compared and some peculiar features of the SDSS-II dataset when standardized with the MLCS2k2 fitter are pointed out . Finally , we construct a statistic to estimate the internal consistency of a collection of SnIa datasets . We find that even though there is good consistency among most samples taken from the above datasets , this consistency decreases significantly when the Gold06 ( G ) dataset is included in the sample .