Depends on the quality of the sight and the quality of your eyes...
Most have variable power so can be turned up in daytime. Your gucci red dot sights will automatically adjust brightness. Cheaper ones will have a tendency to 'bloom' when turned right up. A very bright summers day will show the difference between the cheap and the decent ones.
They don't suit all eyes. I wear prescription glasses and if I'm not wearing them then the dot is smeared all over the place. OK with glasses on though.

To an extent you get what you pay for with these, but there are also diminishing returns. Don't bother buying one cheaper than 20 quid, but for airgun use there's no point buying a £350 one IMO.

Good for garden plinking and fast fire, perhaps hunting at close and/or fixed ranges, but bear in mind that you have no magnification or, in most cases, any extra aim points for holdover/under. I wouldn't put one on a serious rifle. Good for pistols and things like the crosman ratcatcher though.