Open wheelers, e.g F1, Indy cars etc.
or
Tin Tops, e.g anything with a roof, touring cars etc.

or both.

Even though I don't watch much Motorsport, I'll go for Tin tops. I just prefer real cars over powerful go-karts.

Tin tops all the way. OW normally involves downforce and that is just dull dull dull to watch as it just becomes hotlapping.

Open top closed wheel LMP all the way.

Tin tops ftw imo.

OWR are all good but I prefer seeing improved versions of normal models racing bumper to bumper, where it's mainly skill, where as in most OWR championships, it's the team with the biggest budget that generally wins. It's more closer in tin-tops.

I like that open wheelers are purpose designed race cars. They're race cars and nothing else.

Nobody takes Goldwings and modifies it for Moto GPs do they?

I'm regularly watching F1, GP2, DTM and WTCC so I chose "both".

i prefare tin tops