Probably among the best and most addicting game I ever played. The single player story mode lacked character development but made up for it through improved gameplay mechanics, graphics, and action packed missions. There is plenty to do in single player such as playing tennis, golf, racing, etc that will keep players busy. It is a nice transition from the gloomy and gritty atmosphere from GTA 4 because the game highlights the glamorous and greedy side of Los Santos.
GTA Online is also a noteworthy game to play and it has plenty of pros and cons in its own right. The ability to acquire properties, businesses, compete and/or cooperate with players makes this game an immersive experience and it makes you feel like you mature with your character. You will see your character grow from being a petty criminal doing small time jobs for Lamar and Gerald to becoming a successful mastermind criminal. While this kind of gameplay is rewarding, it is difficult and tedious to move up the ranks. This is especially true for those who are full time students and full time employees because they are time constrained. If you are time constrained, barely starting GTA Online, and still want to have fun in GTA Online I do suggest you purchase the Criminal Mastermind Starter Pack. I added additional tips down below to save you the time from watching clickbait 10+ minute youtube videos.
The Criminal Starter Pack will give you $1 million, a CEO office, an apartment, MC Clubhouse, vehicles, weapons, and clothes. These properties might not be the best locations, but they are a good way to start earning money and once you save up enough money you can get better locations. With the money you earn I do suggest you avoid splurging it on vehicles. The only vehicles worth buying right away is the Kuruma and the Oppressor. The Kuruma will protect you when you do missions and the Oppressor allows you to travel quickly across the map. For aircraft, invest in a Buzzard and a Cargobob. The Buzzard is a great helicopter to use in missions due to its agility and its weapons allow easy kills. Being a CEO also allows you to spawn a CEO in most locations. The Cargobob is a must have if you intend to import and export vehicles.
For MC Businesses, invest in the Meth Lab, Cocaine Lockup and the Counterfeit Cash (in that order). Avoid document forgery at all times because there is little profit to be made from it. In fact, it is more profitable to do contact missions than to do document forgery sells.
Once you earn a decent amount of money, you can go ahead and splurge it on vehicles. I do suggest people wait when the car they desire is on sale. Every Thursday, GTA Online will have new discounts and double money/rp events so keep an eye on it on the Rockstar Newswire. Also, buy more businesses and renovations when they are on sale to save a lot of money.