It just feels 100000x better to type on. It makes me want to type out long posts just because it's fun.. I'm sure some people don't "get it" but I hate typing on rubber domes now that I'm used to mechanicals. I'll never go back..
For the benefit of people reading the thread who have not used mechanical keyboards, here's another view. I have both a Filco board with brown Cherry switches and a Happy Hacking board with normal rubber domes. I actually prefer the HH board. For me it's not the switches as much as the layout. Solid feel is also important. Both are usually okay in these "serious" boards irrespective of switch technology - not so much in cheap boards, or "gamer" boards, even the expensive ones. It's like an expensive laptop vs cheap laptop - you are putting a good bit of money in something that cannot be reduced into bullet points, but is massively more comfortable and unobtrusive in actual use.