1. I feel that as with many products, microwaves are also maximized for perceived customer happiness - this means food hot ASAP. So, they're probably pushing out the legal maximum of energy in microwave form. "Better" microwaves are probably worse for this.
2. I notice a distinct flavor to microwaved _meats_ specifically - maybe this is true about all proteins, but I'm not entirely sure. It's very pronounced in more flavorless chicken dishes when I notice it. I've read (on some stackexchange site) that chicken can change when re-heated. I don't need to know what it is. I trust the tongue evolution gave me.
3. I have always noticed - no matter what type of plastic, all plastics impart a taste to water once the water has been sitting for some time. I imagine heat speeds up this process. Maybe, microwaves do too. Again, the tongue.
Based on these points, I:
- avoid microwaves like the plague to start with. Air fryers and mini-ovens FTW! Sometimes it's far and above the best choice; e.g. microwaving nachos vs. burning them with the broiler and wasting a LOT of energy in the process.
- never microwave with/in plastics. So, no TV dinners EVER, and pyrex/glass/ceramic containers.
- generally microwave at 70% or less power rather than the default 100% - usually on a program of progressive power reduction (see below)
- constantly stir/move food around - prevent hot-spots (see next bullet)
- immediately stop the microwave when I hear any popping sounds - it's a good heuristic that some part of the food is boiling hot, and the heat needs to be evened out
One piece of advice is to familiarize with the power settings and "programmed cooking" methods of a microwave. I often will heat food on a program of 70% power for 1 min, followed by 50% power for 1 min, followed by 40% power for 1 min.
I hope some of this helps someone. I feel like I'm the anti-microwave evangelist of the house - my wife heckles me about it constantly. I can't wait to send out this link in the AM!