Just started playing 2 months ago! Caliban has ruined me.

So per the title, just started my journey like 2 months ago. I remember in like the first week of me playing, I somehow got Caliban for free without needing to research or anything. I kept them stashed until I maxed out my initial frame, but when I switched to Caliban, i havent been able to let them go. I've picked up rhino, vauban, and mag along with excal. I've maxed them all but just can't stand their kits when compared to Caliban.

How did I even obtain this frame that has ruined me? I'm not mad, I'm just curious.

Edit. Also, is caliban really that good/easy to use or am I just liking him more because the other early frames are lacking? (Just completed Phobos)