They are hard ones - which by the same token makes them very useful. To given you some insight, I find all this very useful for decisions on what airport to fly out of in London (yes, a very specific example with a lot more commercial airports than other places). I've got a choice of LHR, LGW, LCY, STN and LTN.

So there are a lot of factors to take into account, LHR offering the best connectivity but LCY being small, comfortable and close to the city, with minimal/no queues. The seats are nice and a few shops but not too much due to size - doesn't matter, you only need get there 30-40 minutes pre flight.

LGW is a great base for some LCC and has a nice selection of shops inside, but can be like LHR in terms of population overload at times. Nonetheless, I'm always able to find a seat in both LGW and LHR. Since both have long queues and travel to them can be problematic, I usually arrive early, and find a power port to juice from. LHR is far better at that than LGW. This allows me to watch a show or surf the net for an hour before boarding.

And there are some airports to avoid like the plague if transiting without lounge access - like DXB where seats are always scare in supply, people often sleep on the floor due to crazy connection times, and some shops that don't accept credit cards (I'm looking at you, Dunk'n Doughnuts!).