I bought my 27" iMac seven years ago. It has only required one trip to the Apple Store to replace a failed logic board. It is the best Mac I have owned, but it won't run macOS 11 ( Big Sur ), and Apple may be switching to ARM very shortly.
I like to save up for my big purchases, so I specked one of the current Intel-based 27" iMacs to get an estimate of prices. I noticed that I could choose between a standard display and a "nano-texture glass" display ($500 more). Here's what I learned about that.
To remove dust or smudges from the nano-texture glass screen, use only the polishing cloth that came with your Pro Display XDR or iMac.Apple Support Document HT210229
Apple is the only company selling these specific cleaning cloths. The "Apple Cloth" is $9 each.
The standard iMac glass can be cleaned with a regular microfibre cloth and a small amount of water. On Amazon.com a pack of 10 microfibre cloths is $10.
Submitted for the 100DaysToOffload project.