Hello
Welcome to indigo!
Your work is cool, and we will help you making it better.
First tip, seeing that you have white walls, when you set the color i sketchup, don't use pure white : luminosity at 85/100 is good.
I can see that you have some (phong) reflecting materials (wood etc...) so Bidir MLT shoulb be better. Bidir is good because you are doing an interior scene, but MLT is very accurate for these type of materials. in the first minutes of rendering your image will be scary, bit it will ameliorate very fast.
Your aperture is very strong yes! maybe keep it at 16, or 22, i think you will get the effect you want
I also tried Poduim and Artlantis and other stuff before, but i geve up, because you will see, the time you pass rendering, re rendering and reeeee rendering again with these programs to get the good result, you will render it only once with indigo
Keep going, don t give up! For the speed question, i have the same problem, because the rendering speed is directly proportionnal to your computer, and since indigo is unbiased, time is the price for quality renders.