Hiya! I'm a second year lboro student and have lived in for both, in two different accommodations.
I've lived in butler court and William Morris so I can only give you my honest opinion for them (they are self-catered so if you're looking for catered, stop here 🙂 )
Butler court was my first year accommodation and I'd say it was a good hall if you were a drinker. They rarely did events that didn't involve drinking for freshers (though it might be different each year depending on committee). It's amazing if you take any art or design degree as it's by the design school and the art school (like across the street) but it's a long way if you take STEM. There is a campus shuttle but it's the difference between living for class thirty minutes early and five minutes early. I took graphic design so it was great.
Positive points: If you're shy, there is only three people to a flat so it's rarely busy. The room are incredibly huge (pretty sure they're the biggest on campus) so great if you have a lot of stuff. I had the deluxe room and there was two wardrobes so that was a bonus. It's also only five or ten minutes up to the union so great for that.
Negative points: Super expensive and slightly left out from the student village, so you're often left travelling further to see friends if that's a problem. The common room lacks a little bit but it is massive. Noise levels depend on where you are but you get a lot of road noise as it's next to the main road. There is a slight silverfish problem for those on the bottom floor in the bathrooms.
I currently live in William Morris (commonly referred to as Bill Mo). I adore it here, honestly. I've never felt so happy living away from home than I do here. There's six to a flat so a lot more flatmates but I've made such good friends with all of them! Plus if you are nervous, you soon find you're not cooking at the same time and don't always run into them due to lessons. I'm friends with the receptionist and the biggest bonus is that parcels get delivered directly here, where as on campus halls have a mail room you travel to. It's still a university accommodation that you get through lboro but it is a unite students.
Positives: It's across the road from the student union and it's been crazy how many times I've left to get milk 5 minutes before it's due to shut haha. Life saver. Reception is lovely and everywhere is kept super clean. It's a really good hall vibes to be honest and super quiet as it's not directly on campus (just across the road). It's super easy to get around since the campus shuttle goes to the union. It's also cheaper than Butler but still expensive. En-uite is a little small but never caused me any issues. It's also around the corner from the urgent care centre if that puts you at ease (maybe I'm just clumsy though lol).
Negatives: It is a smaller room but it's the typical size of most the uni accommodations. I know some people don't like the feeling of being in unite halls so that's something to consider, though it's incredibly well run in this one and contracts are through the university. It's technically off-campus if that bothers you. Parking is paid and you have to pay just for visitors to park too but most people just park in the street next on.
I have a few friends living at Elvyn Richards, I've heard that's okay and I've heard the holt is lovely but far. However, I don't know much about the other halls, I'd recommend getting your ideal price before looking more in-depth at them though as they really vary how much you'll pay

Feel free to ask me any questions, I'm happy to help or be quizzed on anything Loughborough!