I don't think there is a correct or universal answer to your question because frontosa variant desirability is highly dependent on personal preference.
Some variants are blue-er or perhaps even violet-ish, some are rarer or less available than others, some are more out going, some have 7 stripes instead of six, some develop larger nuchal humps, etc. Variants which are common and an relatively inexpensive can be just as spectacular as the rarer expensive types.
I currently have three frontosa variants and am considering acquriing a fourth type. I like them all.
As far as requirements go, the care and feeding of all frontosa variants is practically identical.
