Amaterasu and Sol are the two strongest SSRs in the gacha right now, hands down. Every one of their skills is mad useful and they have several rare, fairly powerful skill effects. They're a tier above all the other SSRs (most of the rest have 2 useful skills and 1 meh not terribly excited for skill). Michael might also be at their level, but I don't think anyone else is.

That all being said, if you're already committed on an account, then its pointless to roll gacha for them because its very likely you'll spend hundreds of dollars without pulling one. The odds are stupidly high against you.

If you're rerolling, then those two are great picks to aim for.