I can't say I enjoy them, but I don't hate them, cleaning the house in preparation is the biggest faff tbh....however we do always find lots of socks in the playroom, so even that has its benefits.
We only do group sleep overs in the summer so they can all stay out in the garden in tents, they can stay in there catching up on sleep until the middle of the next day if they want or pile into the house and wire up to the PlayStation and alternate sleep with eating or playing. I barely see them until it's time for a hug and a cheerio, they are not my friends so I don't really interfere, neither are they of primary age, so if they know they have to leave early in the morning for sports fixtures then it's up to them to arrange a lift home at 10 -11pm or understand they may be a bit rubbish and sleep deprived, the same applies if my boys sleep over, if they need to be up early I ask them to do so quietly and politely, do their fixture, then go to bed back at home for a few hours, sometimes they even return to the sleep over house for the rest of the second day, if it's been agreed.
Maybe it's the timing that's wrong for you? Invite them for a late tea, keep them all day after, by the afternoon they are just dozing about in the playroom, enjoying one another's company and helping themselves to toast, returned to parents in time for by 5pm for dinner and sleep. Don't structure their time or feel the need to involve yourself, other than a few rounds of "clear up your mess, it stinks in here, open the windows, here is a tenner go and stock up on bread and biscuits."
Birthdays are different of course, you must also transport them all to some ridiculously expensive activity such as bowling, zorbing, bouncing, or any other "ing" which entails far more effort, but I guess it is their birthday.
I often slept round my best mates house in the summer holidays, her mum worked so we had free reign the next day, my mum just popping by every so often to nag us a bit (we lived ten houses apart), happy days, feral kids, chilled parents. (Yes catseye, we spent far too much time exploring scrapyards, woodlands, rivers, canals and huge empty houses too but I was far from deprived as a child)