Well, the fit is lovely. Tahari's a great brand for you.
But honestly, I would wait. I feel the pattern is a bit much at this length (a bit of extra length might help here) and there is something odd about the sleeve detail -- as you say, that and the neckline are so different from on the model. Frustrating!!
I often find that colours are lighter/brighter in the web version than in real life, so I try to factor that in -- but it's not universal so you really never know until you open the package.
I think it's great that you are on the active hunt already. You will find the right dress and you will look amazing!!