PCGaming

I second this.

About 6 years ago I had to make 20 upper mid teir pcs for a client's art department. I normally build my own but 20 seemed like a lot to do at once so I outsourced it to a company called Xidax.

I could pick the parts that met my spec and perhaps because it was a larger order I was able to get some parts they didn't have on their website after calling and asking. But most importantly it wasn't too much more expensive than a big box store pre-built but with quality parts, not just economy parts you might normally find in a lot of prebiilts. (PSUs and drives are important not to skimp on, especially in enterprise environments.)

I would say, building your own is better. Both from a cost and learning perspective. It's a lot easier then it seems, I know it's intimidating. But if your uncomfortable building your own. Go with a company you can pick name brand quality parts from that will last.

Also, I would avoid water cooling unless your workload demands it. Water cooling is honestly not worth it.

PS if you plan to upgrade it yourself. A case can either be very important or something you replace easily. The better your case is to build in, the longer you might keep it. Case in point. My fractal design silent case is the oldest PC part I have (at least 10 years old) and it's probably never going to need a upgrade.