I got this game and a few others for free with a PS4 I picked up recently.
Does the game play out like a PC MMO where if you are coming in as a new player you have a long slog to get caught up to everyone else ? Also, what is the DLC situation with this game and how does that work ? I'm guessing there is a pile of it as it's an Activision game.
Like others have said getting to 20 can take 15+ hours depending on how you play and how often. Once you get the hang of it you know what to use to level up quickly. The first time going from 20 to 25 will be the hardest because of Gear but buying armor from the vanguard when able will help a lot.
It took me about 3 weeks to get my second character to 28 and 2 days (about 10 hours) to get my 3rd to 24 but my first character took...let's just say longer to get there.
There is one DLC coming out in December which I don't think you're required to get if you don't want to and another next year.