Leeds isn’t ‘far bigger’ at all. Leeds is England’s 3rd largest, Sheffield is 4th so hardly a massive difference.
I’m biased being a born and bred Sheffielder but taking a balanced view, I think Sheffield edges it for me.
Leeds has better high end shopping (Sheff will catch up a little when the retail quarter gets finished), more higher paid jobs etc. Don’t let this sound like Sheffield is poor because it certainly is not. Sheffield has many very wealthy suburbs.
Personally, I find Sheffield a far more interesting place ..... more bohemian ..... more quirky!
Nightlife is great in both cities but the music scene is probably better here. We have great theatres too.
Both have lovely surrounding countryside but Sheffield easily wins in this department.
And yes our tram system is great too.
I’d still rather live in either city over London which is a vile place. I can cope with it for a weekend or so but it’s soooooo depressing and everyone looks depressed. Not for me at all.