I own a few student rentals and those statements have been pretty accurate in my situation as well. I usually have students lining up to rent a room, but few of them stay longer than a year (longest one so far has been there 3).
Leasing by the room is more complicated, more paperwork and people to keep track of but generally is more rewarding cash-wise.
It'll be interesting as I continue to accumulate more properties. I do it for the cash flow, which is why student rentals appeal to me (lower returns with single family homes in suburbia). Eventually I anticipate needing/wanting a property manager, but it only is really crazy during leasing turnover time (the month of August). The rest of the year, I get maybe 2-3 calls about a necessary repair or something. I might look for someone who can offer a cheap hybrid solution, where I qualify/select tenants and send them to the PM company and they just manage the day-to-day operations for a reduced fee.
