Had I known, I would have gotten a different brand.

[atabitaraf]

Had I known, I would have gotten a different brand.

Is it a formal way for making conditional sentences?: Exchanging the place of subject and auxiliary verb!

 

[5jj]

It's perhaps more formal than 'If I had known', but it's fine.

 

[Rover_KE]

Note that most BE speakers don't use 'gotten'.

I'd say 'got' or 'bought'.

Rover