Which amp would you ...

eco1

If you have the chance to own a Matchless Spitfire 1x12 or a TK Head, which one would you choose and why?

TY

Winny_Pooh

A spitfire will break up faster if that is a thing for you. You are really comparing fairly different amps; ac15 ish vs a blackface fender type.
Maybe @Wazmeister could comment 

slacker

I own a Lightning Black Cat and a Morgan DAG I think you know which one I would choose.

Wazmeister

I've owned a Matchless Lightning, and now a Nighthawk...

For live and rehearsal, Ive never heard a 3D room filling sound like it.

Matchless are a bit special, but as @Winny_Pooh noted above, you are comparing two different amps.