My bighit is in the mid 40s - I've never taken it 50, But i have taken it on a handful of 30 milers with mucho hills. Just pedal - and pedal it like it is. The only time I really got hammered is when I tried to ride it like a CC bike on the climbs - if I would have just stayed in the granny I would have been fine.

However - If I had the options you have, I'd take the SS - no question.