I'm glad you asked this! I used to have the same questions and now I feel like I may have some insight. This is my experience:
I worked in a small, rural hospital that had about a 15 bed ICU, a 30-ish bed PCU, and 3 medical floors. I worked in the PCU (Progressive Care aka ICU-Stepdown/Telemetry) and we had ratios of anywhere between 2:1 and 4:1 depending on staffing/acuity. I loved it. Fantastic experience and preparation for my current career in ICU. We had 2 cardiothoracic surgeons at the hospital though and once their patients left the ICU, they only came to our unit and were D/C'd from there. The surgeons refused to let their patients go to the medical floors. They were complex patients with high acuity. We also did vasoactive medications, but we were allowed to titrate only to a point (cardizem max of 10, nitro max of 30, and dopamine max of 5). And I can remember multiple times where our patients were intubated and sent to ICU after Bi-Pap therapy didn't work for them. I also remember seeing a patient in asymptomatic VT. All kinds of good experiences....
This rural hospital was part of a larger hospital network that included many many rural hospitals and several large hospitals in the largest city in my state. I remember Resource Nurses who traveled the entire system would float to our unit and say "Well in the city, the patients are way sicker and blah blah blah." I remember thinking I was glad I didn't work in the big, urban hospitals. As life may have it, I ended up moving to that city and working in the ICU of a Level One Trauma Center of a very large urban teaching hospital within the same health system. I was scared because I thought the patients were going to be super duper sick and scary.
Some of them are. But to be honest, my experience in the PCU at the smaller hospital was GREAT experience. At that rural hospital, they take sicker patients on the PCU because their ICU is much smaller. They only have so many beds to put actual ICU patients in so anyone who doesn't necessarily have a vent or drugs, may get downgraded. At the large hospital I work at now, we have a cardiac medical ICU, cardiac surgical ICU, neuro ICU, medical ICU, and a trauma/surgical ICU (mine). I've floated to cardiac surgery multiple times and have thought "wow, we admitted these type of patients into the PCU at my last job!"
The last thing I think (sorry I realize I'm writing a book!), is that in smaller hospitals, you get a variety of patients (neuro, cardiac, surgical, etc), because they don't have the designated floors like large hospitals do. On the PCU, I took care of multiple acute strokes, and now, if we get even a small head trauma, everyone is like "Oh, no they need to go to the neuro ICU!"
That's just my experience. It could be entirely different in another health system.