Well, seen on its own SH2 is certainly a nice game. But gamers who have played ALL series of SH will tell you that SH2 is at the bottom of the SH ranking for different reasons, one of them being that the campaign is not dynamic. For a dynamic campaign you need to play SH1, SH3, SH4 or SH5 (but not SH2!)
My prefered SH series are:
SH5 + TWOS (Atlantic battlefield)
SH3 + LSH3 (or WAC) (Atlantic battlefield) - @
p55carroll: Can be played on Win7, Win8, Win10
SH1 Commander Edition 1.31 (Pacific battlefield)
SH4 + GFO (Pacific battlefield + UBoat expansion for german subs in Indian Ocean)
SH2 - Not a dynamic campaign but: has tons of modded single missions available to download.
But more important: enjoy the game!