Picking a Stand Up Paddleboard, need SUP Help!
What SUP to buy really depends on what you want to use it for. There are huge differences in quality and shape/design. I originally thought the whole SUP thing was just a gimmick, but I absolutely love SUP now. I've run whitewater, my family has done multiple self support SUP trips in the Tetons, MT, and BC, I love to go on long lake cruises, and I paddle for fitness and have even gotten into some racing. I have inflatables - I keep them inflated when at home so I can just throw them on the car and go, but have taken them as luggage to Mexico, Panama, the Virgin Islands, Belize, the Galapagos, even tributaries of the Amazon. I don't mind the pump but keep them inflated as much as possible so I only have to pump when I go somewhere new. If all your wife and kid want to do is lie on a board in the sun, it probably doesn't matter what you get. If they want to get into yoga or fitness or something else, quality and shape matters. For inflatables get one that can pump to at least 15 psi if they want to really paddle.
I use Red Paddle boards and run them at 17-20 psi. For fitness/touring/racing/whitewater a good paddle makes a huge difference too.
Picking a Stand Up Paddleboard, need SUP Help!
Width matters. Skinnier than 30" and they get very tippy. 32" wide can be a good stable width. Long and skinny means faster but less stable. 10-11 is a pretty typical length for general purpose.
Thickness matters too (that's what she said...). 4" may not provide enough flotation for bigger people, making them super unstable. 6" is better for larger people, two people, taking a dog, etc, but can feel like riding a cork if a super light person is on it.
Picking a Stand Up Paddleboard, need SUP Help!
Red makes awesome boards. Inflate to high pressures for stiffness and last a long time. I've had multiple Red boards and have taken them all over. They are great. The only others I have personal experience with are NRS- first generation boards didn't hold up but seem better now.