Microwave Went Bust - Replace or Repair?

It is with great brevity that I announce the Morton-Wood household suffered the loss of their 3-year-old microwave. The appliance served dutifully in the face of reheating leftovers, melting butter, steaming frozen vegetables, and baking potatoes.  It is survived by a toaster, waffle iron, and a crockpot.

Boo, it really chaffs me that our microwave is caput.  Three years isn't an acceptable amount of time to just die on us already.  We were pretty gentle with it too - no microwave casseroles here!

Now begins the great debate of how do I spend my money to restore a microwave in my kitchen (which after two weeks without one, we have determined we do need).

I see several options: 

Replace: When we bought our current model, it was $30.  I've honestly had no complaints.  Because we just reheat stuff with it and bake the occasional potato, the size is appropriate for our needs.  With three years of inflation, it will cost me $54.99 to get the same exact appliance.

The drawback is that in another 3 years, I would likely run into the same problem.  Some of the reviews online said the microwave only lasted them a year.  Not cool.   

The landfill waste this creates also really bothers me.  Even if you have to replace your microwave every 5 years starting in your 20s, you'd be buying and throwing away over 12 microwaves if you lived into your 80s!

Repair: Our local Sears offers appliance repair.  Their online estimate quotes me at $48.99 for labor - parts not included.  It may be that I only need a $2 part and this would be a good deal. 

But I know nothing about the inner workings of a microwave, what the common problems are, and how much replacement parts could run. There's no way I can estimate how much money a repair will cost, though I imagine I could walk into Sears and ask them to take a stab at what the problem is before actually fixing it.   

Upgrade: If I ever wanted to upgrade my microwave, now would be the time.  The questions is what else would I be looking for and how much am I willing to spend?

The problem with upgrades is that they're always more expensive.  When I look at the top-of-the-line microwaves at Target or Walmart, they're running between $100-160.  They're usually much larger than I need and have options I'll never use. 

I don't need bells and whistles - I need a microwave that will last a good number of years.  Do they even exist anymore?  My mom still has the microwave she bought when I was 2.  Apparently GE was a good brand back in the 80s, but barely anything is designed to last long anymore.

What would you recommend?  How's your microwave treating you?