I haven't ever gamed a lot in my life but its been a long time…
Reading a bit lately it seems a lot of games are now done via clients with Steam being the best, GOG for old games and Origin then i also hear about Humble Bundle and other gaming sites on Oz Bargain.
Can someone explain Pros and Cons of each, i dont know what is good or what to stay away from.
I am not playing High End 2015 games just more so last ten years.
The reason why we have these digital distribution platforms and why we need to run their software to play these games is because of a neccessary evil called DRM. DRM prevents game piracy and illegal copying and redistribution of games, by ensuring that the copy you own is yours only and not stolen from somewhere else.
Steam is a the sole game distributor for many AAA titles and publishers. The publishers choose which distributor they want to go with — Steam is the choice for many because it provides DRM (which prevents piracy), a wide playerbase, advertising, multiplayer lobby / matchmaking, achievement tracking and all sorts of other stuff. If I had to pull figures from my arse, I'd say 80% of titles nowadays are sold and distributed on Steam.
If you want to play the Call of Duty series for example, ever since COD4 you have to use Steam to even launch the game so you're not really given a choice.
Origin is another minor (or should I say, major) game distributor, and they have their own exclusive titles. Mainly Bioware (who makes Dragon Age, Mass Effect), EA Games (Battlefield, Dead Space series) etc.
GOG is a DRM free distributor and seller. They sell DRM free games (many of which are games that used to be sold in optical disk format) and impose no restrictions on when you can play the game and how many computers you install the game on, but they have a very old selection of games. So nothing too recent in their library.
Humble Bundle is a site that sells games in large quantities, with a charitable spin behind it. They typically don't digitally distribute, but they do offer you links to download the game if it's a DRM free title, and a Steam product key if the game is a DRM game. They use a pay-what-you-want model and the more you pay the more games you will get, and you can elect to donate none or all the money to a certain charity.