Seems to me modern microwaves are all pretty good, even the low end ones.
I have a Panasonic Genius "Prestige" with real push buttons, as well as a Kenmore Elite. Both are about 10 years old now. Both are about 2 cu ft. The Kenmore is taller, the Panasonic wider and lower.
The Panasonic is nice and the inverter technology I think is more energy efficient than older magnetic transformer technology. I've noticed the Kenmore, although of the same wattage rating as the Panasonic, tends to heat food slower. On the other hand, the Panasonic has an annoying tendency to direct most of its heat to the bottom of foods, whereas the Kenmore tends to heat more evenly, albeit slower. Part of this may be that the Kenmore has a big wave diverter "fan" on the side of the cooking cavity, which seems to distribute the microwaves more evenly. The fan cover is also amber plastic, which is nicer and easier to clean than the usual mica covers, which can get kind of funky after a while. But plastic magnetron covers seem to be more the exception than the rule.
The Panasonic inverter defrost is nice as well, and I often use it to reheat things like pizza slices.
The Kenmore does great on popcorn. Best I've ever seen on a microwave.
My advice: get the size microwave you think you'll need, and then focus on the controls. If they are not intuitive perhaps another brand will be better on that. I've seen a number of low end microwaves at work sites that are positively demonic in thwarting simple timed cooking.