They are worth it to 12% of all people in the U.S.
Retina display (do you mean camera?) is bought separately. So is retina recognition software. You will need to find a company that makes recognition software for OS X. If you need to run Windows software, you simply install Windows on the Mac. All modern Macs run Windows fine as well as all Windows software.
Photoshop first distribution was March 1989 and it was Mac only. First Windows version was November 1992. More than 80% of pro photographers use the Mac version.
I have found no problem using iTunes in Windows 7, but I don't use Windows more than ten minutes a week (mostly for the many security updates).
I don't use WinSCP, but you can safely bet that any "Win" app is for Windows. If it is an FTP app, OS X does FTP with no added software.
All printers need drivers. Dozens of popular dedicated printer drivers are part of the default installation of OS X. For others (particularly for all-in-one devices) see what the makers site says. Typically, anything from Epson has Mac drives (pro photographers choose Epson 10 to 1).
Speed of a processor and RAM does not change after six months. It's like wondering if a light bulb will be as bright later. What changes is the file system (could develop errors), the space on the HDD (too full means slower), and the startup apps (when you install apps, they sometimes add some startup stuff that slows the system). Of course, a virus or worm can slow the system, too. Over the past ten years, there have been only a few worms for OS X, and no true viruses. A virus is typically designed to damage system files. That is not an option with any UNIX-based system. If you install Windows on a Mac, you can get any malware any PC can get. BTW, one slower for NTFS and Windows is drive fragmentation. Not ever a problem with Mac file system, except when dealing with rendering many huge video files in Final Cut Pro to the OS X drive volume. It would be very amateurish to do video editing with a notebook, and even stranger to render video to the system boot volume. All video pros use a Mac Pro tower with four internal HDDs and perhaps an external drive array. They will be backing up, erasing and starting over every day or two, so that typically keeps fragmentation to a minimum.
Internet speed can change when the style of web pages changes. Today's web pages are much more resource hungry than those we surfed five years ago. Even Youtube has become mostly HD MP4 files instead of those old standard FLV files, so all five year old computers are slower now because the web pages are loaded with advanced features now.
As for specific hardware add-ons, check the site for it, such as Logitech, to see if the device needs drivers (most BlueTooth devices do not), and if the site offers both Mac and Windows drivers.
You really need to just walk into any shop that sells Macs and look at one. All Macs except the Air and Mac Mini have DVD burners. For those, buy the external burner if you are among the few people who still buy DVDs. Any DVD burner can burn CDs as well. Not all DVD burners can burn dual-layer DVDs, but all Apple computers with DVD burners can. Apple is leading the march away from optical disc. All new Apple computers have hidden partition for system restore and Internet restore (works even with a blank HDD), so if you use NetFlix or iTunes for buying movies and music cheaply, no need for optical disc at all-- except to install Windows if you want to use Windows. I have Windows installed on three of my Macs, but I never use it. I don't play with games, and I don't think about "Does this app come in an OS X version?" I think "Can I do this task?" About 99.9999% of the time, I can do it without Windows.
I think Yahoo Answers has a limit of 10 question amendments, so I'm done with all the extras.
There are some exact features of Apple computers that attract folks. You have to decide if those features make sense for you....
-- Aluminum uni-body case for durability.
-- Firewire 800 (on all but the Air) for faster copying of files to and from and external HDD, and for target disk mode.
-- Thunderbolt for even faster copying to ext. HDD (20 times faster than USB 3.0), and for target display mode.
-- EFI firmware for faster boot time and less trouble with software-hardware setup (no BIOS).
-- Mac ROM for advanced features, such as one-key boot to a Startup Manager (system boot selector), 4-key reset of NVRAM, and ability to install both Windows and OS X with no buggy hack.
These "components" are found on 0-1% of PCs. That means the Apple brand computer is not "just like a PC" at all. It has advanced hardware design that most PC geeks are not even aware of and usually don't even understand.
An overly-simplistic view would be that a BMW is just an over-priced Chevy-- has the exact same specs, four wheels. This view is most common among Chevy owners.