I've had my old YJ with soft top on and most snow it's seen was 2' held up good and was plenty warm (it's a JEEP thing) of course I pushed most teh snow off after I warmed it up. Oh yeah even had soft upper half windows then (damn if them didn't suck) JMO I would still keep the hard top around for when something happens to the soft top and you don't have to wait x amount of days and spend 500-1kl for another soft top right away.
Never owned a hardtop and I live in Mich and have never had any problem with too much snow. Just push it off. And I disagree with RubiconIT when it comes to the half windows I love them and wouldnt have a jeep any other way.
I have been pretty happy with the new softops on the 2003 jeeps.
Combine them with full doors and you have a really well sealed quiet vehicle.
If you get any really heavy snow, just clear it off every once in a while.