I use several. Here's why: Yesterday I was looking to fly and UAV Forecast Conditions said I should be good to go, however when looking at the UAV Map I saw a TFR due to a VIP visit. Heading to the FAA site gave me the details on the TFR which didn't start for 12 hours. And AIRMAP confirmed what I was discovering on UAV.
UAV has settings that let you choose what you want to have shown in the display and the range for each type of site (Small/ Medium/ Large airports, Sea bases, heliports, etc.)
AIRMAP also will ask you "what kind of mission" and provide the general rules for the location you are located at by GPS coordinates. If you zoom out on the display the list will grow to include locations that are probably out of your flight range.
In a different adventure UAV said I had cloud cover - but I don't mind cloudy days so I thought I would go fly. However checking on KittyHawk the actual cloud level was 425' AGL so that put a stop to that morning flight.
My approach to it is to study and know the rules and laws, check several apps, know what airspace you are planning on flying in by using a sectional chart (link below) and make an informed decision from there. I hope this helps.
FAA Sectional Charts in PDF can be downloaded for free from here:
www.faa.gov