I think most use the top feed for fine detail or small amounts of paint application or stencils, at least that is how I use it. The top feeders also tend to come with finer needles too for really fine work. I like being able to spray larger amounts of paint like Pearl white for bellies and it is easier to hook up a bottle then to keep adding it to a top load cup. Now that is just me I am sure others will have different opinions. Like I said the bottom feed Iwata with a few color cups pretty much will cover both uses and the Peak is a good deal and pretty much able to do the same. Bear air is very expensive on their shipping though so i don't do business with them any more. Heck they are right down the way from me and they really sock it to you in shipping. The cups can hold small amounts of paint and then you can strap on a bottle to do more substantial amounts. I prefer a larger compressor tank, 12 to say 15 gallon, so i don't have to hear it cycle on, which you will get with a pancake type compressor. I turn mine on run till it shuts off and I am pretty much good for the rest of the day, but what you have will work just fine.
These guys are where I bought my stuff. They used to have free shipping over 50 but those days are gone i think.
Iwata Eclipse Airbrushes T-Shirts Automotive Motorcyles Helmets
I use the Badger color cups. They fit my Iwata fine. I have found them at Micheals and A C Moore too.
Airbrush Depot Cups