You've gotten some good advice on numbers, payload being the biggest enemy usually. I have the HD payload package and 2200 lbs capacity, but it gets used up quickly. We're a family of four and an occasional guest, add in bikes, firewood, tools, sometimes generator, not to mention tongue weights around 1100 lbs. I often tow a couple hundred over my GCWR of 15300. Other than lacking some power on bigger hills, the rig handles the weight beautifully.
The other part of the equation is the smaller engines like to spin higher to get the job done and some folks don't like to hear that. I just consider it music. When the hills get bigger and the air gets thin, be ready to spend a lot of time in lower gears with the RPMs up unless the 150 has a larger engine (6.2 or EcoBoost). My 5.4 L doesn't come to life until about 3800 RPM but will pull overdrive (4th) on flat and moderate highway hills. I'm sure the newer versions with the six speed do better.
