I have been very tempted to purchase the Mac Mini for my pro work - - - and if I settle down in the future, most definitely will. For real work it will handle my needs quite well.
For several years I have been following professional photographer and photo writer David Brooks on his use of Mac Minis - how successful and economical that can be. The latest Shutterbug review I could find was of an older lower spec'd machine than what is currently available.
http://www.shutterbug.com/content/2011-apple-mac-mini-affordable-dream-computer-photographers
For myself, I have been running a basic 2007 White Macbook (non-pro model) until the power supply went on it this summer. I replaced with a new 13" basic Macbook Air - despite so much being written on the web about how it won't handle serious applications. I'm glad that I didn't pay attention as I love my light weight little gem.
I predominantly use Lightroom 5.3 for all of my pro and travel work - and my little Macbook is up to the task. I have Lightroom libraries with thousands and even tens of thousands of images in them. I process the files in Lightroom using all of the editing tools available - including spot removal, adjustment brushes, gradient and radial filters. I print out straight from Lightroom, export and save for web and full size with adjustments, open into Photoshop 6 from Lightroom for more advanced edits, send to my pro print lab in California - files that have been processed and saved in Lightroom.
The basic model has a 120GB Solid State Drive - - - but that is just fine with me as my practice for many year with my desktop workstations, is to only use the main internal hard drive for OS and programs. All of my data is read from and saved to external hard drives.
With my new Air, I can use USB 3 Hard drives and my portable 2TB USB-3 WD read and write at a satisfactory speed for any of my work - - - and that includes video creation and rendering. Yes I also regularly process images in Photoshop CS6 and video in Final Cut Pro and am able to work in those with ease.
True that a faster machine, may render out a video more quickly or a ton of layers and heavy processing in PS may run more smoothly, but I have nothing to compare to and am fine with the way things are accomplished on my laptop. Something that is to die for with my Macbook Air, is the amazing 10 to 12 hour battery life. Nothing can beat that when you are all day in airports and airplanes and you don't have to charge up.
The Mac Minis are more powerful than my Macbook Air and so that is why I would have no issues using a Mini or two as a desktop computer with a nice monitor attached. I'm thinking how nice it would be to have a Mac Mini that I can take with me in my carry on bag - and have a monitor in Canada and one in Nicaragua or whatever other country I happen to be in - so that I can benefit from a desktop experience.
The exception may be if I was in the video or high end computer animations business where a ton of processing power can be a benefit in rendering times or handling massive file sizes and multiple monitors. Then a more powerful machine can save time and will work better. A lot of such a decision will depend on your expectations (and probably budget). No one can answer that but you.