Churn out terrain with warlayer.com's Zone One
One major benefit of 3d printing terrain I never thought about before owning a printer is, that it is litterally doing all the hard work. If you are set up to remote control your printer, you don't even have to be in the same place (Usually you'll use Octoprint, I also have a remote killswitch connected to my Hue bridge, so I can turn off everything once a print has completed).
This means that I am able to start a print every morning when I leave the house. When I come back in the evening, a new piece of terrain is finished. Cool. I tend to print smaller pieces between 6-10 hours because I don't like printing overnight, but this is not a big constraint.
This is where reliability again is super important. There are many great models available for free in the community, in fact most of my favorite ones are free. In my experience bought models tend to be of higher quality in average. They just don't need as much time fiddling around to get to the desired result. Chances are, that when a print has successfully started, it will finish just fine. No nasty surprises.
Right now, my go-to collection is Zone One from warlayer.com. It perfectly captures the asthetic of the Warhammer 40k universe and has a huge range of models. Initially, this was funded on kickstarter, but it is also available as a late pledge directly from their website. They recently added some models of the ruined gothic range, these are the ones that for me hit the sweet spot between printing time and style.
Pictured above is a part printed in 4 sessions and airbrushed in about 30 minutes. The time painting the model was the only time invested in actual work. You can't get much faster.