I travel 3-4 months a year, usually not staying in one place for more than a week.
I have both bags.com cubes and Rick Steves cubes. I like them both. I use the smaller cubes, mostly 8.5x 11 or smaller. If you open my carryon bag, you'll just see the cubes, no loose clothing. Similar things in all go in the same bag.
Underwear in the smallest bags, tops in a medium (8.5x11), pants/skirts in a medium, same with sweaters and jackets; and electronics in the smallest bag I can get them into. Shoes fit in another one or in between the bags. I use the RS toiletry bag for toiletries, makeup & medicines. I use quart and gallon-size freezer zip-lock bags, especially for anything that might leak. Somehow I've collected a bunch of small fabric zippered bags that I use for jewelry, currency, a small camera, miscellaneous paper, notes, sticky labels, cards, etc. I like the ones that have a see-through panel of plastic or mesh so I know what's in them without opening them.
Advantages of packing cubes:
1, It's like having a small dresser in your suitcase! you know what you are looking for, and you can go right to the right place without rummaging through everything. My bag stays neat.
2, The bags compress the clothes so you can pack more efficiently. I do NOT like the vacuum bags, they take way too much work & time.
3, If your luggage gets searched, TSA or another country's agent will have a very easy time and your "delicates" won't be seen by whoever is rubbernecking next to you. Also the agents won't repack your bag, so you won't take so much time putting it back together.
4, Because of # 1-3, you'll have a lot less stress. You'll take less time to pack each day, and your things will stay organized in your hotel room.