Reckon it’ll be rubbish with MTB tyres, not tried it though. Rollers might work a bit better. I’d try and get hold of an old/cheap wheel that you can put a slick tyre on to pop in when on the turbo.
Also worth getting something with variable resistance (e.g. a mag turbo or some resistance rollers) as mtb gearing is usually too low for most trainers without it.
Rollers are fun, you need to stay quite focused to keep upright (or at least I do, but then I’m still new to rollers) and you can feel you are working your upper body more. Turbo can be a bit of a brain out experience but easier if you just want to churn away in front of the telly. I reckon the two are fairly complimentary and use both a lot.
If it was just to keep the legs spinning over winter and not for any specific programme of training, I’d probably go rollers.
