I ordered the 27" iMac with 8G of RAM and the standard 1TB HDD (from CTS Warehouse). The specs on this 2015 machine are quite respectable when compared to the latest and greatest 2019s now available and can be had a fraction of the price. No doubt, every year Apple improves these machines, either in price or capabilities. That said, both the 2014 (MF886LL/A) and 2015 27" iMacs support the 5K resolution of the newest generation. The 2014s actually do slightly better on most benchmarks than this 2015 (due to a marginally better CPU and GPU  -- check out everymac dot com to compare the features and specs), but the 2014s were originally sold for hundreds of dollars more. Consider a 2014 if you can get it at a better price. As I recall, the comparable 2019 iMac beats the performance of this iMac by about 50% or so (a 6 vs 4 core CPU probably being the main reason). Although the 2014, 2015 and beyond support 5K, the color accuracy has improved in later model years. Keep this in mind when considering which model is right for you.I had no idea what to expect buying this 2015 iMac. What condition would it be in? Would it include mouse and keyboard? Would they be Apple or third party? I was fully prepared to be disappointed and ready to pack up whatever I got for return. I ended up getting way more than I expected. The machine was in pristine condition -- indistinguishable from new. Instead of a 3rd party keyboard and mouse, it came with an Apple USB keyboard and a Magic Mouse 2. The keyboard had some dings only noticeable at close inspection and mouse was also in good condition.Overall, I'm thrilled with my purchase! But be warned. The prices of these iMacs (and others) vary day to day. I picked mine up for an unbelievable price of under $600. The next day, the same model's price shot up to almost $900. I was so happy this one, I bought another 2014 for my son for $650. Likewise, the price increased to over $900 the next day! At $600-700, these iMacs are a killer deal! At $900+, obviously, less so. Good luck!