I've been using mine for about 4 years. The hottest days here run close to 100 and we get those heat waves a few times per season. My house is very-well insulated with high-thermal resistant windows. My cooling area is about 500 sq ft, standard 8-ft ceiling (non-vaulted, no high-ceilings). I run one ceiling fan and two floor fans to move the air-conditoned air around.
My advice to you is to buy the largest BTU unit you can find...I believe the largest portable units are 14,000 BTU. Portable units above this do not exist...you would have to go central. Important to note with the hose(s) coming off the portables...they get hot and I have insulated mine with a pair of fleece-backed x-long sweat pants...that's right, sweat pants slid over the exhaust hose. I also put weather stripping around the edge of the window panel that holds the hose to the window.
What else do you need to know? I'll try to help.