I've been disabled since I was 17 when I was diagnosed with an autoimmune form of arthritis. I walk with a cane and often have to use the motorized carts at grocery stores to get around, due to extreme pain in my back, hips, legs, and hands.
At BYU, I have had mixed experiences.
The faculty in the University Accessibility Center really does as much as they can - I've only had good experiences with them.
Professors and advisers have overall been accommodating and understanding, but there is definitely room for improvement.
One improvement that comes to mind is accommodations with tests. Currently, the policy is that disabled students have to let their professors know beforehand if they are going to need an extension on exams. This is particularly hard on students with unpredictable chronic illnesses. I can be perfectly fine (perfectly fine as in capable of functioning and getting myself to campus) the day before a test, but be very sick and in incredible pain the next morning. Luckily this hasn't happened to me yet, but I live in paranoia of the day that it does happen. The day where I cannot get out of bed the same day as an exam is inevitable.
As for other classroom accommodations, some professors are lovely and amazing and so helpful, but not all. It's discouraging when a professor shrugs and says that they "guess" they will give you an extension on an assignment to accommodate your disability. Luckily, the vast majority of my professors have been more than understanding, but I cannot speak for any professors outside the humanities and religion departments.
My main complaint is with BYU Parking. It took me over a year to figure out BYU's policy on where students with disabilities can park, because only until about a year ago was the information clearly displayed on the website. For over a year, I was never sure where I could park, even though I have a handicapped placard. Now I know that I can park in any parking lot, in any slot (excluding those reserved for service vehicles, deans, or specific placard numbers) as long as I have my placard up. This information took way too long to discover though, and there were several days my first semester at BYU where I put myself in a lot of physical pain by parking in student lots, which are in horrible places a great deal away from the main campus.
If the parking office could simply be more transparent about policies and where disabled students can park, that'd be awesome.
Also, there is a severe misunderstanding of disabilities on BYU campus among students. The common belief is that disabilities have to be at least somewhat visible to be a real disability. Conditions like blindness, deafness, the use of a wheelchair, down syndrome, and other obvious disabilities are accepted and never questioned (and this is good!) but less visible conditions and invisible illnesses are constantly scrutinized. My first semester at BYU, I was walking to class, and a guy said to me, "So you don't have a limp or any handicap, but you walk with a cane." I was stunned at his ignorance, and quickly explained that without my cane, I would develop a limp and be in a lot of pain, and then I walked in a different direction, uncomfortable and not wanting to interact with him anymore. Other people have also questioned my cane, and it's easy to tell that they don't fully believe that I have arthritis, because I do not look disabled, and I'm very young when arthritis is considered to be an old person problem.
There are also other disabilities that are not accepted or understood by students. ADHD, dyslexia, autism, bipolar, and other mental illnesses and conditions are often shunted to the side when disabilities and mental illnesses are discussed. Often, discussions end up focusing on depression or anxiety, which are severe and concerning conditions, but are often caused or made worse by the same factors that are constantly ignored by mainstream media and thought. Discussions about depression and anxiety are good and important, but too often they are the only disability discussed, and the discussions are often very shallow. Depression is often spoken of as feeling down, lonely, and sad, when it is much more than that, and many people don't realize the effects that it can have on a person.
Most students are simply unaware of disabilities and what they entail, and this leads to a lack of understanding and compassion. Abled students will look at disabled students with pity, when we do not want to be pitied! We want to be listened to, respected, and treated like normal people - because we are normal people! My disability does not make me less of a person, and it doesn't take anything away from who I am.
As for general accessibility, I've found that many buildings could be improved by simply having signage that indicates where elevators are, and making sure that at least one elevator is functioning properly. Signage that reminds students to not block the hallway may also help - often students stand in clumps, causing hallways to be congested, which makes it difficult for people with canes, scooters, or wheelchairs to maneuver. Reminders to look up from phones every so often could also be helpful - I have lost track of how many times people have run into me because they were looking down at their phone instead of where they were going. As for wording on signage, words like "handicapped" should be subbed with "disabled", which has less of a stigma and is more generalized, meaning that it includes a wider group of people..