If you take a look to e.g. McSema https://github.com/trailofbits/mcsema, these guys have been able to use LLVM to transform assembly back to LLVM intermediate representation (IR). The IR is an abstract language used by LLVM during compilation to optimize the generated code. Being abstract basically allows to use optimizers across all LLVM supported architectures.
In these terms, I think LLVM has a clear advantage over competitors.
The following blog post give a nice overview of the McSema achievements: http://blog.trailofbits.com/2014/06/23/a-preview-of-mcsema/
What you did with McSema was really impressive and I’m glad discussing with one of the authors! I get the point you regret using LLVM, it seemed to me to be the best choice since LLVM has wide instruction semantics implementations, that more basic tools such as Xed do not offer. If I get it correctly… you would rather re-implement such semantic yourself? Or have you got any other tool / idea I’m not aware of?
x64dbg: http://x64dbg.com/
Where is the request form?
Been using it for a while and like it allot, has a great interface for reversing and diffing win binaries. Will be keeping an eye on Panopticon, looks promising :)
Metasm: https://github.com/jjyg/metasm/
Radare: http://radare.org/
Capstone: http://www.capstone-engine.org/
Capstone is based on LLVM, that you cannot beat in term of architectures and industrial quality, and has great plugins, which make it kind of my favorite.
Of course, for non-scripting needs, you need decent graphical interfaces, as provided by these ones:
IDA: https://www.hex-rays.com/products/ida/
Hopper: http://www.hopperapp.com/
IDA is clearly the best, but Hopper is a fair choice if you need it and you can't afford IDA license for personal use.
[Edit: add forgotten IDA and Hopper...]