I think VHDL makes things easier. Verilog has some fundamental nondeterminism: http://insights.sigasi.com/opinion/jan/verilogs-major-flaw.h... Still, HDL in general is probably on the order of difficulty as getting used to pointers. If you've already done a bunch of work with breadboards and logic gates it's even easier to grok. Of course a lot of people just instantiate a CPU core on the FPGA and program in C...