Hi Frank. If you ask me, I a complete road biker, but still the Thunder MTB is one of my favourite bikes. Mine has drop handlebars and slightly slimmer tires, but I like the stiff frame, which makes pedalling that much easier. In fact, I used to like my Hero Hawk a lot until I added slim tires to the Thunder.
Your height and weight will not be an issue. I am 5 10 (though a lot lighter than you, but that is not relevant) and saddle height and handlebar extension is fine for me.