Yea, thanks for the reply, but I can honestly say that I still won't play the game until this issue is fixed. I just went and played the existing old version on steam and checked my FPS on that. I put the settings maxed out on everything there with 1920x1200 and it still reaches 60fps but with the odd place dropping to 40-50. even at those framerates the game is just about playable. Putting various shadow sliders and vegetation down to medium pretty much gives me 60fps constantly on the old engine.
With the new engine the only real change I've noticed in the brief 30 minutes I've played in total is an improvement the character textures and lighting effects. I'm sure there are others but I wait to see them in the future. As the frame rate is so low, the choppy effects the game has as it is, it's missing frames pretty much gives me the same impression for the locations as it was in the original, which is a kind of pixelated effect. Basically it's moving the camera around with my left mouse button (left handed) that makes the game so hard to look at as everything is so choppy.
I understand these things take time to fix, but I'm sure the people over at the steam forums wouldn't mind some reassurance about the issue. In the meantime, as dblade suggests, providing us with an option to at least try to see what happens by messing with the framerate would be nice. Heck it might even provide some feedback to help fix it

I will put the game to one side for now and focus on the plethora of games I have yet to get my teeth stuck into. Shame though, because my plan was to start another run through from the start, as the first time around, even with the last engine the game was amazing and hugely underrated by many.
I sit and wait for a fix - go give them coders a kick up the backside!