For those who may be wondering about this in the future:
The Hopital Aleman is incredibly efficient. Most of the time you will want to enter to the left entrance on Pueyrreddon into the Policlinic. You walk right to the cash/reception people and tell them what you're there for.
I wanted to see a doctor so I paid for a walk-in visit and they gave me receipt etc and number. I waited about 5-10 minutes. My doctor (who had a resident with him I believe) was great, competent, friendly and offered to speak English or German as well. (not sure if German was really an option or if a translator would have come in)
The doctor noted since I didn't have insurance the hospital was one of the most expensive places for bloodwork and I could go elsewhere if I wanted. He didn't know the prices but said I should inquire with the PR/marketing/repuestas people. So I did. Went to the office (near main reception), someone came to me right away, made a photocopy, went back in, and came back within 5 mins with a breakdown of the costs of each blood test. In pesos they did add up but in dollars I was fine with it, plus I just wanted to keep everything simple/central at the HA.
With my orden for bloodwork I went to the lab area. Paid. Got a number, and had my blood taken within about 5 minutes. The results were ready two days later and can be obtained in person or via internet (although you have to sign up for that when you pay).
Amazing experience overall, I was in and out within an hour. I've been back since (to get a px, more bloodwork, see a specialist etc) and it's been equally amazing. Some specialists may take a while to get an appointment with BUT most also have walk-ins available if you go and wait.
Costs: each time you see a doctor or specialist it is 210 pesos or $48 CAD.
Basic but extensive bloodwork: around 700 pesos or $160 CAD (includes CBC, cholesterol, blood sugar, thyroid TSH/T4). Actually the more specialized tests were by far the costliest (thyroid tsh/ t4 being about 140 each).
Other more specialized tests seem to also be under 200 pesos but may take a while longer. However, for the more specialized tests I thought seemed to take a bit long to have results back, both Rossi and Schere would have taken significantly longer.
All this to say, extremely happy with the service of the Hopital Aleman and would suggest going there. Compared to US prices, or Canadian potential for delays, definitely proves to me that a two-tiered publc/private health care system is the best and most effective option.