Buy a window unit if you can. Cheaper, more efficient, quieter. (Those of you in stratas, check your bylaws, alot of them do not allow window units, they are a hazard since they are never installed properly)
In regards to noise, if I'm not mistaken, every 10db higher the rating is, the noise doubles.
50dba = noise
60dba = 2xnoise of 50dba
70dba = 4xnoise of 50dba
AC units need to be sized properly. You cant just buy a unit and expect it's going to cool.
What does this mean? Go on Google, and research BTU of cooling required, to get yourself a rough idea
Ex. 6 people in 900sqft condo, plus kitchen, plus 4 computers operating, huge south facing windows (30,000btu required)
Vs
2 people in 400sqft condo, plus kitchen, one laptop, small north facing windows. (10,000btu required)
Ps, those of you looking at dual vs single hose portables, dual hose units are far superior to single hose units.
Mini split units are the highest end option, far more expensive, but a no brainer if budget and bylaws allow them