Yes differant brands are better than others. Do alot of reading on the reviews. I find thats the best way to get the answers you want. Profoto is some pretty awesome stuff.
I own the D1 air system but dont but their umbrellas or soft boxes. Way to over priced. Shoot through umbrellas are at the bottom of the quality of light list. They waste alot of light by spreading it everywhere. Plus some of the light gets reflected away from the subject. Next on the list is the bounce type umbrellas. Little more control but not as good as softboxes. Do you need softboxes. Absolutley not. Bouncing the light of walls and ceilings is also a very good way to create a light source. Remember the larger the light source the softer it will be on you're subject. If you want further control, thats where grids, barndoors, honeycombs and snoots come in. Do alot of research and try and learn as much as you can because good lighting is key to awesome photos. Another thing, not all monolights are the same. Just because it says 500ws doesn't mean it is. A good you tube video that explains the differance between ws is from Marc Wallace on Adorama TV. Worth watching.