I've seen both and each has its own qualities, but one is a recreation of the original play in a more literate modern interpretation and the other the Stephen Sondheim musical version. The Winstone version was filmed in Romania for the BBC. Angela Lansbury was the performer Sondheim had in mind for Mrs. Lovett and Len Cariou as Sweeney which was the original Broadway cast. I saw the original cast on stage in New York and prefer Len over George. Cariou was just plainly a better actor and singer than Hearn although Hearn was able to hold the weight well enough.
The play and the musical are distinctly two different products and the melodrama is played up in the musical, understandably so -- it's suppose to be black humor and wicked fun. The Winstone play version is more seriously involved in why Sweeney became a serial killer and it's pretty much played straight (and even bloodier than the stage version, though I suspect that's what inspired Tim Burton to bring on the unabashed horror in his film).
WOW,didn't the Brits do well.Who would have expected LONGFORD or AWAY FROM HER to walk away with an award.Next up is the BAFTA's.Anyone want to make any predictions?