The best mini-ITX PC case is about being able to build a powerful gaming PC into the sort of footprint normally given to a games console. It's a challenge for sure, and the need for more expensive ...
The only real difference between the two is that a custom prebuilt PC will allow you to tweak the specs and configuration to your specific liking, such as a different case, cooler, and various other ...
The HP Omen 45L isn't just my favorite gaming PC, but I've even built a complete custom PC in its case myself, and that's not something I'd even attempt in most prebuilt gaming PC chassis.