This is ours, cheap and cheerful. It does a good job of our 1 bedroom flat (full sub-ground floor of a terraced home, so not a small 1 bed). On some of the dampest days, which incidentally seem to happen when it stops raining after days of rain, it lags a bit and I might need to wipe things down in the morning or maybe at night. But that's it, and it beats doing it over and over again. I would not go without it. Most days we run it half a day, but I am looking forward to shutting it down except for the most humid days this summer. We've been running it the past few days at winter levels, but it's really been bad the past few weeks in regards to rain.
I use it instead of running a tumble dryer and it works great.
ETA: Our flat has vents in every room which are always open, and they don't seem to help at all. Maybe it would be worse if we didn't have them or maybe our flat is just a bit worse because it's effectively the basement, but we had a whole wall dripping in water the day before we bought our dehumidifier. I don't think any amount of window cracking would help that. There's been no sign of that or mold, and as I said, maybe on the dampest day light condensation on the windows in the morning.