Well, Tomahawk is more expensive. And I won't tell you the exact reason, but I was just going through the same dilemma and went for PC Mate. Maybe it was many people talking about it making issues with the 1600? Or with overclocking?
NOTE that i also went for a 3200MHz ram (because Ryzen), so maybe it was just that it doesn't support these speeds. Anyway, i chose to let it pass for a reason - so please make sure it's all good and compatible with your build before buying it.
Best of luck