2. I'd say apples and oranges is subjective and depends on what is important to you. If you're interested in Vitamin C, apples to oranges is a valid comparison. My interest in comparing this is for running local coding LLMs - and it is difficult to get great results on 24/32gb of Nvidia VRAM (but by far the fastest option/$ if your model fits into a 5090). For models to work with you often need 128gb of RAM, therefor I'd compare a Mac Studio 128gb (cheapest option from Apple for a 128gb RAM machine) with a 395+ (cheapest (only?) option for x86/Linux). So what is apples to oranges to you, makes sense to many other people.
3. Why would you think a 395+ and an M4 Pro are in "a different class"?