I've installed just about everything on this list. It all depends on what the specific application is. Overall, if budget allows, I think the Skull Canyon NUC's are pretty rad...quad i7, 32 gigs of RAM, dual NVMe drives, and the ability to hook up to an eGPU box ($500 Razer Core + up to a GTX1080 via reddit testing), which makes it perfect for an office PC, a CAD workstation, a gaming rig, etc. Very cool device!
The Dell 7040's are nice; I've actually be using them a lot for mini-servers lately. No standard RAID array in the SFF version (single M.2 + single SATA), but with incremental image backups & a spare drive, no worries...that catch is worth it because of (1) the tiny size, and (2) the NVMe drive speed (plus you can get a 4TB Evo SSD if you need a decent amount of fast internal storage space, and single-drive 10TB USB drives are available now). Plus vPro in place of an iDRAC...I've found a surprisingly number of server-related applications for these little puppies. I just did a site where they did a primary domain controller with one (AD/DNS/DHCP/File Server/Print Server), a secondary domain controller, and an offline "hot spare" using a trio of 7040's. Amazingly quick! If either machine crashes, it's a piece of cake to restore the last hour's backup from a Macrium image, and if the machine itself dies, they can simply grab the spare & swap out drives in minutes. Crazy easy. It's not your traditional Dell or HP server with special remote access cards, RAID boot & RAID storage, yada yada yada, but for budget-oriented projects, they are super neat!
NUC & BRIX computers are great for home users on a budget, because you can build them pretty cheap. Even though I like the Skull Canyon NUC's, regular models are much easier on the budget, and most consumers don't need anywhere near 32 gigs of RAM (despite being so cheap!). I'm also very interested to see where the Compute sticks go in the future as the die sizes shrink...next year, we get 10nm Ice Lake chips, so they might improve by a whole bunch in 2017.
Overall tho I just love mini computers...Raspberry Pi's, NUC's, you name it 😀