Finally saw this movie tonight. I thought overall, it was a good film, and worthy of the franchise. If I were to rank it, I'd place it right behind <SPAN style="FONT-STYLE: italic">Alien</SPAN>, and ahead of <SPAN style="FONT-STYLE: italic">Aliens</SPAN>, with respect to quality.
I thought the character dialogue could have been strengthened; David was too front and center, at the expense of characters that faded from supporting to peripheral in nature; that lack of depth made their respective destinies less important to me.
I like the backstory, and it certainly sets up nicely for a sequel.
Overall, I'd give it 3.5 out of 4 stars. It was the best sci-fi film I've seen in a long time. I would recommend it to any sci-fi fan in general, and certainly to anyone who liked <SPAN style="FONT-STYLE: italic">Alien</SPAN>.