Unfortunately, most such upper-crust thorough companies have long since been run out of business.
Reason being, that property managers like yourself, will always SAY they want quality. Yet, what they DO, is to take the lowest bid. I mean, think of it: if several bidders are there looking at your places, and they were to ask you: "do you want quality?", OF COURSE any property manager is going to be compelled to say "yes, I want quality". But then what they turn around and do instead, is to take the lowest bid of the guy who flies through like a batt out of h*ll.
I saw this happen over and over and over again when we used to do shopping center type sweeping (we are now strictly big rig sweepers). And when I would go back 6 months later (like if I was happening to go shopping there or whatever), I could/would see how the sweeper isn't slowing down to get grit, and isn't blowing out the back-most corners, isn't getting nails and heavy debri up (just papers). So on a few occasions, I'd point this out to whomever I'd given the bid to. And guess what? They'd invariably not care. They'd see me as being a competitor with nothing but a "sour grapes" syndrome
(ie.: someone trash talking their competitor).
So even though you say you want quality (an obligatory thing for any manager to say), you're going to have a hard time getting parking lot sweeper guys to believe that. They'll know/assume you're going to choose by price, and therefore they'll endevour to quote the the lowest price, right? And we all know what happens when that starts up: If you're only getting $XX for a property, the vendor is going to be subconsciously always time-conscious (lest he go out of business spending too long at each stop).
About the only way I can figure is to ask the prospective vendors for a list of their other customers. Then simply go look at those accounts. Be looking for sediment buildup along curbs, sediments pancaked down in the corners, grit accumulation in low spots. etc...
Be sure to get as many references as possible (lest they merely give you a few that are in good shape, simply because perhaps they underwent a recent seal-coat).
If you have larger industrial/commercial type properties (rock, dirt, etc...), let me know if THAT'S the type properties you were/are referring to.