I will agree that fly is certainly a safer mode of travel outside, unless you leave the safety of the ceiling and aggro a sniper on a rooftop. Then it can get you dead fast. This is understandable, but it does add to flight time as you have to make sure to fly upwards to get significantly out of any aggro range. Indoors flying can be a tricky (and sometimes risky) choice. Some tunnels/caves/hallways are too narrow or low ceilinged for safe flight. Hover can make up for it a little, but has to be heavily slotted for it to be more beneficial than just sprinting.
The speed of flight is relative. In some zones, flying can be more beneficial over other travel powers. Faultline, Boomtown, Dark Astoria, The Shard, and Skyway come to mind. With a decent slotting in fly, you can usually take the crows path to your destination while your teamates spend time finding that elusive slope or stairway to head up.
I think the speed cap is a little low relative to the endurance cost, though. Combine that with the -Acc, and the power looks a lot less appealing for most. As I've seen stated on numerous occasions, the travel powers that come from a set that has "more useful" powers over the whole set get picked more than the Flight PP. Most people seem to want Hasten, so SS is a natural choice later. Some people really like having Recall Friend, so Teleport is often taken as well. This hurts the Flight PP overall, since a good many people see Hover as essentially useless. I disagree with that, but to each his own.
I would love to see one of the three often made complaints with Fly improved, but it does keep the airways clear enough for those of us who do choose to fly.
