I rarely agree with cyccocommute about much anything. On this one he is completely correct, it is a matter of technique. Back when I was a lad, which is a very long time ago, everyone was taught to ride ‘light in the saddle’. There was sort of enforcement on that, clinchers then were very slow, if you wanted to ride much it was tubulars. Tubulars were even more fragile then than they are now. Tubular rims were very fragile indeed, they flatspotted if you looked at them wrong. If you could manage to get light in the saddle the bike needed a whole lot less maintenance. Even now, bikes ridden lightly last much longer. And of course there will be comfort.

Other things being equal more weight will be supported by the legs if your saddle is back and down. In any case experiment a lot with position. Move things around. But wherever the saddle ends up good technique is mostly up to the rider. First step is to know it is possible and to keep it in mind.

If you did nothing at all the Giant should still be more comfortable than your old Trek. Should be six or seven pounds lighter. Think of your bike as a hammer and your butt as the anvil. A much lighter hammer is going to do much less damage. The Giant also comes stock with decent tires, way more compliant than what the Trek would have. Most compliant tire going currently would be (in your size) the Rene Herse Snoqualmie Pass, 700x44. Like riding on clouds compared to OEM on your Trek. The Giant is a whole lot more bike than an FX2. Not a crack on the old bike, but you are stepping up several levels here. Enjoy.