I've had mountain bikes in both those brands and liked both. I second the seat advice. I'd not only get gel, I'd buy one designed for a guy's anatomy. The anatomical saddles help keep pressure off of certain key components.
If you wife is an enthusiastic cyclist she has probably already educated you as to the importance of some functional bike shorts. If lycra isn't you style you can get ones that have a bike short liner and looser shorts outside. The ones my hubby likes look like cargo shorts on the outside.
