We've stayed in quite a few in England & Scotland.
Bogglehole (near Robin Hoods Bay) - fantastic YH & Family room. Basic but clean, food amazing, right on beach, but not an en suite (this doen't bother us)
Boswinger (South Cornwall) - lovely small YH, Food fab, 5 mins from glorious beach, no en suite.
Straford Upon Avon - massive YH, not as personal as the others but great facilities, food and en suite.
Scotalnd - We went to Stirling and stayed in YH there. It is a huge hostel and not very personal but right in the middle of the city, just next to the castle, with en suite and the breakfast was awesome.
We couldn't get into the YH in Edinburgh as the Fringe was on, and we ended up in Travelogde. It was awful. It was actually cheaper than a YH but it was scruffy, unfriendly and food was plastic.
We LOVE youth hostelling. We usually get a family room even though there are only 3 of us - one big bonus for us is the other familys from all over the world. DS loves it. He spent 3 hours teaching 2 spanish boys to play cricket!