I’ve just moved over to them from Sky. Early days yet but a couple of months in and initial impression is that it is better. I wasn’t on Sky Q or anything, but the box is better, software is better and it works better. Not missing any of the channels I cannot get anymore – with sky it is definitely a case of paying for a lot of crap you don’t need or use.
I’m sure it is probably the case that Sky is still the best, but you don’t half pay for it and it is no longer the only game in town.
Give it a try. Ditch sky, give BT a go, you will be able to get it cheap enough on an introductory offer, if you don’t like it go back to sky as a new customer on a better deal you could have got as a long term customer.