For less than the price of a mini I got an old aluminum-tower 2010 Mac Pro on craigslist, swapped in a used hex core Xeon, 32GB of ECC, raided SSDs, and a GTX 750Ti. It does use kind of a lot of power, but watching node compile in a minute or two (about 4X faster than my iMac at work, sigh) is nice. It Geekbenches just below a 'bottom end' new Pro.