Depends on cost of repair. If it's a couple hundred bucks and you're otherwise happy with the dishwasher then repair it. If you replace it with a low-end Bosch it will be about $1000. If you get a better, quieter model it will be hundreds more.

How do you find it for loading? I'm concerned about going from the American style racks (seem to be more accommodating of different sizes) to European style racks. I hand wash my nicer pots & pans and put the less nice ones in the DW. I also put my glass lasagna pan in fairly often, and it fits just perfectly in the Maytag. I do love the 3rd rack option.

I'm not too concerned about sounds b/c we don't have an open concept house and our TV is in our finished basement.

Assuming you have sales tax and require delivery and/or installation a low end Bosch will be around $1000. I have a 20 year old Bosch at one house and one that's a couple years old at our other place - both great. I recently sold a home that had one about ten years old. It needed some repairs at about five years and I considered just getting a new one but they didn't have the color/style I wanted so I got it repaired. It's been fine since then. My newer ones are 800 model in part because I did want the lower dB level.

I don't have a problem with loading - once I got over the idea everything would line up perfectly like the pictures. I'm fussy about things not being too close together or clanking into each other so I don't cram it full like some people do.

That's not the complete part. You can fix this yourself.

1. Browse to Maytag MDB8959SFZ4 dishwasher Parts
2. Click 'Upper Rack and Track Parts' in the left-hand menu.
3. Expand the diagram.
4. The part is #2 if it's the Dishwasher Dishrack Adjuster, Right
5. The part is #2A if it's the Dishwasher Dishrack Adjuster, Left
6. Note the part number.
7. Search Amazon and ebay for the part number.
8. On Amazon, these parts are about $50 but that's a lot less than the cost of a new dishwasher.
9. Refer back to the rack diagram. The parts are attached to the rack with one screw. You can attach the new part to the rack yourself.

I would examine the part that is not broken on the other side of the rack. If there are no obvious cracks or deficiencies, I wouldn't replace it. It's lasted eight years and may last another eight!

I think I am going to replace. I just don't have a lot of confidence. The wheels broke off last year, plus something else broke and we can no longer adjust the height of the upper rack. I feel like we would just be bailing out a sinking ship. But I DO appreciate you looking all that up for me. I tried briefly but I am not handy at all and didn't understand what I was looking at.

"we can no longer adjust the height of the upper rack"

The rack adjuster is the part you need.

"I feel like we would just be bailing out a sinking ship."

Nope.

"I tried briefly but I am not handy at all and didn't understand what I was looking at."

You're "not handy at all" because you don't try. You see part #2 in the diagram. You need part #2 or part #2A and either one attaches to the rack with one screw - shown in the diagram.

I mean that I didn't understand when I tried looking for it myself.