Midsized microwave recommendations?

I have a Kenmore microwave that I got three years ago because Consumer Reports recommended it. I had a LG before that that I only had for two years before it bit the dust. I was just trying to melt some butter in my microwave a few minutes ago, and sparks started emanating from the microwave. It reminded me of fireworks. I then tried a cup of water and no sparks. I then put the butter back in with a cover over it, and sparks started flying again. I am afraid to use it again.

I just got on Consumer Reports website via the Evanston Public Library, and looked at the ratings for midsized microwaves. The top choice is a LG that is $165, but when I read the reviews people left, there were only two reviews but both had the microwave die on them within a year. The next two microwaves on the list were Panasonic, and they both got mostly lousy 1 star reviews because they also died within the first year.

Does anybody have any good experiences with midsized microwaves they would like to tell me about? The microwave I had before my last two was a Whirpool that was a return at Sams club, It quit working for the original owners, and was shipped back to Whirlpool where it was repaired. I only paid $50 for it, and it lasted me for five years.

The last time I had to buy a microwave it seemed like Best Buy mostly had LG, and I did not want another LG. I really don't want to pay more than $150. I just had to replace my tv too which was probably only seven years old. I got a really good deal on an open box at Best Buy though. I got a 43" Sony 4K for $262 including tax.

This is confusing because when I tried to melt the butter I got sparks, but not when I tried to heat up milk. I realized my microwave was really dirty, and now it is a lot cleaner. When I just tried it with the butter again, it sparked, but it might have been the lid I was using because when I switched to a different lid it did not spark. I will just have to keep a close watch on it for the next few days when I microwave anything to see if it acts up again.

Any type of metal or non microwave safe material in that top? Just a thought.

That is what I maybe thought that there was something in the lid, but the lid is from one of the Rubbermaid 6 quart containers that is supposed to be microwaveable. I think it was just my microwave was really dirty. I heated up an Eating Well dinner late last night, and it did just fine. I thought I had had the Kenmore for only three years, but when I looked it up on Sears, I bought it 9/14. Thanks, Nancy