I just finished DC yesterday, and to me it was decent experience. Not as annoying as other forums posts would say.
Was there backtracking? Yes, but I backtrack through the whole game anyway to due to loot/merchant system, so it was not a big or new issue.
Also, most of the areas are empty, so backtracking was not painful.
Ark station was fantastic experience, deep worms section was boring but quickly finished, mushroom section required looking into wiki to figure it out and mutogen puzzle was not too difficult to figure out on its own, yet due to its placement it can be easy to miss it and just straight go to the endgame.
I did not like creeping dread mechanic, but it was not too annoying experience, since only several maps use it, and they also have little or no native monsters (just snails), so you can just get in and get out quickly. Also, Leo helps a bit to make it easier.
Only time I had larger battle with Tchortlings was when I was scanning mutagens in the lab and then writing them in the notepad. Luckily, I fist locked lab doors with the card, so I could do research in peace. At least until I opened the door.
I only rerouted Ark power twice total, so not too much backtracking there. It just made sense to first power up residential section and warehouse B, since they are the closest to the plant. And later power two other sections (mugotens and lab) and that's it.
Anyway, game logged 4d13h for my whole playthrough (108h), 3d21h when entering Deep Caverns. So my playtime of DC took 16h total. Yeah, I know effective time is more due to save/load, but still not close to "stuck 40h in DC" horror stories.