As ever, the key is monitoring and airmanship. I regularly fly with colleagues who start paperwork or generally non-pertinent stuff before top of climb rather than monitoring. As galaxy flyer says, flying. An aircraft with VS only acquaints one closely with the required technique and pitfalls. One's hand is almost permanently twiddling the VS knob at high altitude and it becomes second nature very quickly.
If one is used to flying an aircraft with VNAV/FLCH/OP CLB, for the majority of the time reacting to minor speed trends is not required so you become desensitised to it. Then, when using VS close to OPT/MAX, a wind shift or lack of attention can cause problems.
Like anything, it is a tool to be used when appropriate, rather than banned by SOP-heavy airlines.