Newer versions of OllyDbg never caught on and a stable working x64 version has never hit. The main community for Olly sort of died with XP 32-bit unfortunately. x64dbg has largely replaced it for 64-bit code and many of its common features and plugins for 32-bit code on 64-bit OSes too. Unlike Olly, x64dbg is also open source, which has lent to some interesting features, though it's still largely the work of Mr.Exodia as far as I know.
Of course, debuggers like x64dbg fit a niche for when you need to do a lot of dynamic work, like dumping data or unpacking an executable, they're not static analysis tools like IDA or Binja, which you'll probably want if you're analyzing algorithms and trying to understand the inner workings of something.
EDIT: I have a [dead] reply saying everyone moved to Immunity that I'd like to respond to. There's some truth to that in some communities, but the catch there is that Immunity never got good x64 support either. To my knowledge, it's basically just an Olly fork with some additional scripting features and stuff, doesn't solve the 64-bit problem or the 32-bit on 64-bit OSes problem.
I guess it wouldn't even exist if OllyDbg x64 would be a (non-alpha) thing. x64dbg provides a number of plugins in order to fill missing features to IDA/Olly: https://github.com/x64dbg/x64dbg/wiki/Plugins
Looks like a very interesting project, but maybe there's some misunderstandings about the license; from the readme:
> x64dbg is licensed under GPLv3, which means you can freely distribute and/or modify the source of x64dbg, as long as you share your changes with us.
Should probably read: "... as long as you make genuine offer of providing the source code and changes to those you distribute your version of x64dbg to."
In practice it of course makes sense to upstream changes, but there's nothing in the gpl about that.
That's fine, and it is of course how many projects use the GPL in most cases in practice -- but as it reads in the readme, it sounds like the GPL doesn't [allow] someone to fork the project, port it to say, OS X, or arm - and sell the changed fork to a to a customer without giving the changes back upstream. The porter would have to offer sources to the customer, and the customer would be free to upstream the sources - but from the GPL, there's no legal compulsion to do so.
Anyway, I guess I would have reworded it somewhat, to make it more obvious that the source is under GPL, but that the project welcomes and encourages upstreaming changes. This opposed to the code being under a modified GPL.
I used x64dbg recently, because I had to debug Win64 code and both Ollydbg and IDA Free don't support it.
I like the x64dbg UI a lot more, I loved the persistent breakpoints and it was just very easy to pick up and work with. I found one shortcoming: it doesn't have an inline memory viewer - but it can export a memory section to a file.
