This iMac is in great shape and perfect working order. It has a 1TB Fusion drive installed, which is a bit slow during start up, but once it's up and running it feels quick and totally functional. It can also be upgraded to a SSD with the right tools and know-how. It's running macOS Ventura version 13.7.8, which was released August 20th, 2025 (but it won't run Sonoma or later).
RAM was upgraded to 40GB which means you won't get bogged down when lots of windows and applications are open. It has an Intel processor so you could even use Boot Camp and run it natively in Windows! Note that Windows is not included, nor is a keyboard or mouse... but if you aren't picky I can throw in a PC keyboard and mouse.
Specs are here: https://everymac.com/systems/apple/imac/specs/imac-core-i5-3.4-27-inch-aluminum-retina-5k-mid-2017-specs.html