I never used it, so I can't give any anecdotes. But the 'implementation' section of the wikipedia about this topic cites some hardware and compilers. I quote some parts of the article:
Hardware: "Native support of 128-bit floats is defined in SPARC V8 and V9 architectures, but no SPARC CPU implements quad-precision operations in hardware as of 2004. POWER9 (ISA 3.0) will have 128-bit hardware support."
Compilers: "Quadruple precision is specified in Fortran by the real(real128), or as real(selected_real_kind(33, 4931)), or in a non-standard way as REAL*16. (Quadruple-precision REAL*16 is supported by the Intel Fortran Compiler and by the GNU Fortran compiler on x86, x86-64, and Itanium architectures, for example.) (...) in C/C++ with a few systems and compilers, quadruple precision may be specified by the long double type, but this is not required by the language (which only requires long double to be at least as precise as double), nor is it common (...) some C/C++ compilers provide a nonstandard quadruple-precision type as an extension. For example, gcc provides a quadruple-precision type called __float128 for x86, x86-64 and Itanium CPUs, and on PowerPC as IEEE 128-bit floating-point using the -mfloat128-hardware or -mfloat128 options; and some versions of Intel's C/C++ compiler for x86 and x86-64 supply a nonstandard quadruple-precision type called _Quad"
Libraries and toolboxes:
"The Boost multiprecision library Boost.Multiprecision provides unified cross-platform C++ interface for __float128 and _Quad types, and includes a custom implementation of the standard math library.
The Multiprecision Computing Toolbox for MATLAB allows quadruple-precision computations in MATLAB. It includes basic arithmetic functionality as well as numerical methods, dense and sparse linear algebra.
The DoubleDouble package provides support for double-double computations for the Julia programming language."