Leg room? The the least of your problems....
Many of my fellow low-costers complain about the leg room available on planes. Come on, quit whinging. Don't you like playing middle-aged sardines?
Never one to follow any trend, leg room isn't one of my grumbles. Torso room, however, is. Never mind the length, what about the width?
To be a modern low-coster you need the flexibility of an Olympic gymnast - and eyes in the back of your head. On a recent flight I'd settled down into my usual routine.
Seatbelt on - check. Book open at relevant page - check. Coffee ordered from trolley-person - check. Tray down, on which to rest said coffee and book - check. Eyes in the back of my head scanning the aisle behind me - err, no.
Result? Coffee, released from its styrofoam jail, in left hand. Lift cup to mouth. Shift elbow 20mm into aisle to enable liquid to reach mouth - and have flight attendant knock elbow. Coffee on book, tray and trousers. Comment from said flight attendant?
"You really must be more careful, sir."
I think it was the "sir" that got to me. Just a little too much emphasis on that single little word. Nothing at all to do with the fact that he'd knocked me.
Sorry really is the hardest word.

Cabin baggage allowances
Don't you love them? Having done a quick check of the main low-costers, they all appear to have different acceptable measurements for your carry-on bags.
So, if you travel frequently with, say, Easyjet, and follow their online advice on dimensions of your holdall, trolley-dolley wheeled bag, fancy computer bag etc., you'll be fine. There won't be a problem.
But try taking the same bag on Ryanair and you face problems - you'll need a smaller bag unless you want to hear those dreaded words: "Sorry, sir, that bag exceeds the carry-on size - it'll have to be carried as hold baggage. That'll be £40 please."
So, if you travel frequently, use the lowest common denominator - which, as far as carry-on baggage is concerned, is Ryanair.