I like the elitedesk PC for smaller services. My main reason being the power draw and or heat output. The ones I have and plan to use 60w of power which is pretty damn good for a whole computer.
Noise is another factor. Space saving is a plus, helps prevent ewaste since these are almost always refurbished. Its a good deal IMO.
And you can always buy or build a big honking PC or server for something else later on.