Personally, I think there is a big difference between Deore and XT. However, I would NOT recommend XT to a newbie, or relative beginner. Why? Well, because you break stuff initially. As you become a better rider, you crash less often however, with the same severity.
Here's a tip that may prevent future destruction. Only tighten your shifters/levers/stem/handlebars/bar ends/etc. to the point where they are snug and won't move under medium pressure. But not soooooo tight that they won't move at all. That way, in the event of a crash, your shifters or levers will twist on the bar, but not break!
L8R
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"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
"Your Bike Sucks" - Sky Yaeger