I use LLDB with some regularity. The last I checked, lldb is essentially at feature parity with gdb in user space (not sure about kernel debugging), and has additional features beyond that aimed at fixing some of the mistakes of gdb.

As a small example of something LLDB got right, say I want to put a breakpoint in this C++ template function:

    template<int X>
    factorial() { return X * factorial<X-1>; }

Because it is a template, this one line in code maps to multiple program locations (factorial<1>, factorial<2>...) gdb will create a separate breakpoint for each location, and each must be managed separately. But lldb maintains a logical / physical breakpoint separation: one logical breakpoint maps to multiple breakpoint locations, so you can manage all of them as a single value, and more easily treat factorial as if were a single function.

(Maybe more recent gdbs do this too - my version is rather old.)

One downside of lldb is that, while its command line syntax is very regular, it's also quite verbose. gdb's 'attach myproc' becomes `process attach --name myproc`. gdb's `up` becomes `frame select --relative=1`.

lldb does have a set of macros and abbreviations that cut down on some of the verbosity, but they haven't always worked well for me, and I hope they overhaul the syntax.