I read a lot of reviews; starting with the 1-star ones and while some of them state that aircraft aren't modelled properly, I'd have to ask the question (to them) - then why are the US Air Force, French Air Force and other air forces around the world either using or planning to use DCS for initial combat pilot training? Eagle Dynamics must be doing something properly if those air forces are queuing up to procure DCS.
The learning curve is definitely high. Unless you're dedicated to spending hours to learn every aspect, then it will take a lot of time to master it. That can be frustrating. I think they could do with more tutorials.
But, from what I've experienced, it's incredible.
Please note, however, that in addition to a moderate specification computer (I only have a Alienware 15), you'll also need a decent "hands-on throttle and stick", i.e. HOTAS such as a Saitek X56, Thrustmaster Warthog, Virpil and WinWing (in order of cost) but there are cheaper ones available. I started with the Saitek X56 because it has a built-in twist grip for rudder action. You'll also need a head tracking system, e.g. TrackIR 5, or a VR headset, e.g. Oculus Rift S or HP Reverb G2.
So, besides your computer, you could spend anything between $US 400 (or for me, £360) for an X56 and TrackIR but I since invested in the Thrustmaster Warthog as well as the Thrustmaster TPR pedals. I also use the Oculus Rift S headset but I intend to invest in the HP Reverb G2 soon and buy a much more powerful computer.