Some common courtesy goes a long way.
If someone asks your opinion before they purchase, that's the time to throw out what you think of the choice, be it brand, size, or options.
But once they've shelled out their hard-earned money, the decision is made. It's the time to offer congratulations and compliments, or let it be. Negative opinions wont' change anything.
If your friend gets married, you don't tell him at the wedding reception that his new wife is a trashy gold-digger. You tell him before the wedding, or you keep your opinion to yourself. It's too late to fix it, so there's no point in raining on his parade. That's what my Grandpa used to tell me, anyway.
The OP chose a very fine, capable truck. It should be reliable, safe, and well suited to his purpose. It's not as if he's lugging around an oversized trailer with an undersized tow vehicle. So it's time for a thumbs-up and a bit of class.