The main difference is easy

Quietness, so you can work sleep etc + more space.

On a side note you may be lucky enough to see a young man from Maryland taking photos of bogs, crew seats, food, wash bags, pax manafest lists........ All this will only be possiable if he hasn't been arrested, had is camera taken in a OW lounge, had his bagged knocked of a trolley by a foreign lady, been chated up for being a fashion designer or more than likely never taken the flight because he is in dream land.

toodle pips.