Which are the programs that are better than Beyond Compare now? I’m using WinMerge and WinDiff at the moment but not really happy with either of them. (WinDiff has a terrible UI. WinMerge has a fairly poor diffing engine that sometimes gets confused over simple changes.) Coincidentally I just downloaded Beyond Compare but had not yet tried it out.
I looked at the “comparison of file comparison tools” link but those tables are horrendous and I can’t be bothered filtering out all the meaningless stuff (e.g. I’m only interested in Windows GUI tools so the OS X and Linux and command-line tools just get in the way).
Jeff, You mentioned that one or more tools are now better than BC but you didn’t say which they are. 
As comments that other people made about free and/or open-source software not being at risk of developer neglect: Absolute rubbish. Plenty of free and open source projects have been abandoned. Unless someone is actually willing to put the effort into a project it doesn’t matter whether or not the source is available. I myself and a programmer but I don’t go around fixing/improving other people’s projects very often. I do occasionally but in general I simply don’t have time. I imagine the same is true for most programmers, especially when we’re talking about large projects where it may take you a day just to get the thing to compile and then even longer to get up to speed with all the source and the architecture of the thing.
If software is free (as in no cost) and/or open-source then that’s always a bonus, but IMO a very small one compared to whether the product is actually any good and has good developers actively working on it, something that in my experience is completely orthogonal to the cost or visibility of the source-code. The “thousands of eyes” is a complete myth, IMO, and many of the big open-source projects (like Firefox) are successful because they have dedicated paid developers working on them just like a closed-source project.
(Before anyone jumps on me: I am absolutely not saying that free or open-source makes things worse. I am just saying that I think people overestimate how much they make things better, and other aspects are far more important.)