... other than being a better performing/compressed/etc. format than vcd, obviously ;)
My typical workflow to look at waveform dumps is to convert vcd to wlf and use ModelSim waveform viewer (instead of GTKWave+). A major annoyance is that this strips (or I don't have the begin with) the direction of the signals. Everything is a wire.
Other than capacity, are there reasons why I should consider trying lxt2 and gtkwave again?