Well I'm pretty new in SB pro pe, I mean I had two one month licenses about a year ago but I ended up not having the time to go deep into it or at least not as would have wanted to, each time.
So I recently bought the usb license to be sure to have the time (this time). However, that's where I see the line between "game and hobby" I'm not new to simulation since the "realism feelings" is what I seek, even if I don't have any experience what so ever with the military.
It's just that "classic" games, meant to be played by many (kids included), are IMHO somehow "dull", you spawn you shoot you die and so on...
In a simulation what you do really matters, you have that feeling of "being here" and you have to learn to do the most basics things. That's why I spent a lot of time in DCS already and why I'll do the same on SB.
So far, for me, learning new fire control systems are not the harshest thing. I can't say that I really master anything but, for an exemple, some days ago I jumped into a BMP-2 and I went to the wiki to know how it works, how to use the ATGMS and in no time I could do the basics with it.
For me the true "big step" will be to understand the "tactic" aspect of the game; how the interface in the map really works, how to lead your forces and what tactics to use, how to set up support sections, how and when to use it... Or even how to order infantry to assault a position without being butchered.