I have always been a 'One tool for one job' kind of guy.
I have always used MC for audio, but not for any other task.
With MC 12 I find it is more than capable of my day to day tasks.
I have a digital camera that has RAW capability. Previously I used specialized software to process the RAW images to jpg.
MC 12 does a very nice job on these files 99% of the time. The remaining ones are so badly shot that it takes lots of processing to get a usable image. But the ease of using MC for the other 99% is what I like.
Sharing the pictures with others is something I like. MC 12 has the ability to create an online album with just a few clicks. Even creates a TinyURL for you to send to those you want to share the images with. Very cool. Beats other online photo services, and its free.
I've compared the ripping ability of MC with EAC and dBpoweramp R12. Much easier for me to use and gives at least as accurate results. Speed is on par with the others in most cases too.
I have Chinese in-laws. I love the ability to queue up some traditional Chinese music, get a slideshow of images together, then have the music play while the slideshow cycles the pictures. It is an ability that everyone I've shown it to is impressed by. In fact, they have favorite shows that are asked for again and again.
We have LOTS of portable players here. iPods, iRiver, Creative, no name devices. When people stop by and say "I like that song, what is it?" I can plug their device in, let MC scan it, then sync a song or two to their portable. Much of my music is in Wavpack or FLAC, and MC converts to a nice MP3 rate for the portables automatically. Again, impressive to the folks who stop by and see how easy it is to do this compared to how they are used to getting music onto their devices.
Like Doof, is there one thing that I like best about MC other than this forum where I can ask any question and get a lucid answer quickly? Nope, it is pretty much the whole package that I like. I don't notice from day to day how much I rely on MC, but this made me think of how many ways I use it, and how "invisible" most the cool features are because they just work.