I'm asking this question as someone who has greatly enjoyed the use of mechanical keyboards for years. I will say that without a doubt I enjoy typing on a mechanical keyboard more than any rubber dome or scissor switch. My current keyboard is a WASD v2 with Cherry Mx Browns, and I dearly love it. Yet I type more slowly on it than I do on a scissor switch keyboard. On my mechanical keyboard I can reach up to 120wpm with 1-2 mistakes per minute, or 110wpm consistently without mistakes. Yet on my Lenovo laptop with scissor switch keys, I can get 120wpm without mistakes, and can reach 125, and sometimes 130 with 1-3 mistakes per minute.
In the end, I'll take comfort over the slight speed increase, especially in long typing sessions. But the reason for this I think, is that the keys on my mechanical board are raised, whereas on my laptop keyboard, they are flat. I find that when typing at very high speeds, often the edge of my finger will nip the key next to the one I'm pressing, which doesn't happen nearly as often on the flat keys on my laptop. Another thing that may affect speed is travel distance. Scissor switch keys only travel about 1mm, which means less time pressing the key.