The MS-1 are not made cheaply, but they have a slightly rough appearance due to the older manufacturing equipment Grado Labs uses. So you'll notice small marks at the bottom of the plastic cups, near the cable openings. I think these are flash cuttings from the molds used to make the cups. Some people will notice slight variations in the cables - most of them are 100% straight, but they do have a slightly handmade appearance at the Y-connector. Mine are fine.
When I first got my MS-1s, I couldn't stop looking at them. They have a strange kind of beauty that takes getting used to. A lot of what you'll read here is exaggerated and based on a few bad units coming out of the factory. I can't find any other problems with my pair other than the marks mentioned above. Please note that I also own the Grado HP-2, widely considered to have the best build quality and aesthetics in the field.
My MS-1 have survived 3 years in my backpack jumbled with books, camera, laptop, and various other gear. Frankly, I'm surprised that they've survived this long under those conditions. They have a strangely tough/fragile reputation that is difficult to explain definitively. Some issues that you might notice over time:
1) The silver lettering gets rubbed off with contact. This is easily remedied with any silver paint.
2) The pads fade in color slightly, turning a lighter brown or green color. You can either dye them, leave them as is, or replace them. Mine still look black in most lighting, so I've left them.
3) The cables get tangled. Untangle them by turning the drivers and straightening the cable.
4) Grattle. Sometimes a hair will get stuck in the driver - causing a rattling or vibrating sound. Remove the hair by blowing in the driver or using tweezers, etc.
5) Breakage. This doesn't happen all that often, but it's possible to break or separate the parts that hold the sliding rods. Since they're glued, this is relatively easy to fix.
That's about all I can think of at the moment. Once you get over the niggling details, you might even enjoy the music.
