My advice
I have had one over 20 years and love it.
1. Keep it simple and it will be reliable
2. No wood on the outside
3. The only thing we had to replace was the 1HP motor. Same heater over 20 years.
I like the blue colors becase it makes the water look better.
We have the typical two inch think lid that really works pretty good.
110V or 220V is ok.
Cost to run per month Average around $25 in HB.
Costco or Sams Club
Yes I second no lay down seats!