Most liquidity of course.Yes all major currency pairs are well for trading. They provide us fast movement rather than working with non popular pairs. They are losw in spread , trading in these pairs is ging on daily in up or down positions. One can make some pips easily if he is good in trading skill. It is good to get small profits to choose major pairs as a beginner. Yo nee dnot for a long time to wait moves f the pair. In a day they normally move upto 200 pips.