Out of curiosity, I had a look at App In The Air. I totally agree with what others said before, it is just too cluttered. Sometimes it even gets it totally wrong like showing a delayed flight that didn't take off yet as in the air, or reporting a delayed flight as landed with an arrival time in the future.

My favorite so far has been The Flight Tracker, but I would appreciate a little more information like the plane type e.g. Besides that, many times The Flight Tracker does not display the gate numbers.

Thus, I decided to take a look at Flightlogger. Looks nice, has aircraft information, seems to have most of the gate numbers. What I find highly irritating though is that a trip of 4 legs gets displayed in 2 blocks of 2 legs each. The first block contains the flight date, leg 1, and leg 2 with next day arrival. The second block contains the next day's flight date with leg 3 and leg 4. Can't find any way to change that.