We have mashers like numbers 1 and 5, but both are heavy metal and we've had them for over 40 years. They are both built like battleships, which is probably why they've lasted so long...and tons and tons of potatoes have been mashed using them. We also have a ricer.
As others have mentioned, the desired texture of the potatoes dictates which one is used. Most the time, we like potatoes with a few lumps. Probably a throwback from the days of eating instant potatoes served commercially that were nothing more than glorified wallpaper paste with salt.
The ricer is used when ultra-smoothness is the goal. I also use the ricer to process hard-boiled eggs for egg salad and to squeeze cooked spinach.
As for your questions, I'm a home cook, but have raised 8 children so I guess that, at times, qualified for cafeteria-style cooking, especially since most of the children were boys.
I already explained my motivations for which one I use and, as far as meeting my expectations, I couldn't be happier. They've served me well for more than 40 years.
Each tool is well-made, comfortable and easy to use and I wouldn't change a thing about them.
I can't imagine even considering purchasing a "power" masher since our kitchen is already filled to capacity with powered gadgets. The only power I've ever needed is my two hands and they require no batteries and don't go down during a power failure.
Not that there's every been a "mashed potato crisis" in our house during an electrical outage.
Best wishes with your project and let us know how you fare.