Product review (4 stars): Closeness of this type being vulnerable to steam from cooktop
Don't know why this style became so popular as I see a major flaw that is really no fault of microwave, but seems as a solution would be addressed put into action.  My kitchen cabinets were customed made in 2007 for this popular style of microwave over cooktop but my first very good microwave started with problems 4 years later progressing to less functions in 2012 and completely stopped in 2013.  Repairman confirmed what I saw as a problem with so much steam from alot of activity on cooktop getting into the electrical works of microwave.  Now with my new gas top, I had to adapt counter to raise it 3/4" and then another good inch or so for height of grates...so now even closer to microwave.  But since my cabinets were built for this type of installation I'm stuck as not enough counterspace to have a separate microwave (which by the way I can buy a comparable one of those for so much less cost).