I went to I Am Legend last night, it was decent. The film you are referring to BV was in the 90's with a 'bigger' budget filmmaker behind the helm, not sure who.
I am a big fan of Matheson's novels, and so was nevertheless slightly disappointed in the movie.
I can honestly say, despite it's 'kitch-ness' I enjoyed the Omega Man more, but for what it's worth, here are my thoughts:
The Good:
Will Smith's acting, believe it or not. He does a good job at portraying alot of the pathologies that the main character in the book portrayed. He's believable and definitely creates some pathos.
The Bad:
Story deviation. In the novel, Matheson, like in the movie, becomes the antagonist to the 'vampires'. However, in the book, and I think what's a little cooler, the 'I Am Legend' stems from the new 'still-living' vampires fearing Neville. He becomes a 'legend' who stalks and kills the still-living, being a legend in that sense. The movie would have had more of a pull for me if they would have done that.
The Ugly:
The ****ing CGI was butt-****ing horrible. Seriously. I've made better FX with a box and a sock puppet.