Lots of opinions already, but ill post mine since i just recently (1 month ago) switched to mechanical for first time in my life!
So someone here told its like SSD vs regular HDD.... Sorry, this is just my personal opinion so dont judge me, but i dont feel like that AT ALL.
The difference between good membrane keyboard and mechanical doesnt feel so huge. At least
i dont feel it. Only reason i could think why i dont feel it because i had high end (and meant for gaming) membrane keyboard before, maybe thats why i dont feel like i went from hdd to ssd....
Do i think its better than than membrane? Honestly, too fast to tell. At first (week 1) i was very underwhelmed by it because its whole different way how it works! Best example is - key spamming!! For membrane keys register when they reach the end of its way (when you push it all the way down), but my new mechanical has Cherry Red switches that register like when button is pressed about 1/3 of the way down... In practice, when i spam a key in a game, the way you spam it has to change, because on membrane i could keep key down and move it up just a tiny tiny bit to spam it, for mechanical i have to keep it somewhere up ... its even hard to explain, but you have to find the sweet spot, and its not easy to get used to... but you do, eventually.
Is it worth it? Whats good about it?
I dont know, but i think its worth it because, good membrane costs just a bit lower than decent mechanical, so id say why not go for mechanical IF you ened new keyboard or your old is trash.
In the end it is somewhat much more nice to play on, i dont know how to describe the feeling but it feels different in some way, sorry iam bad with words and English.
Did it improve my gaming? Um no, not for me. In fact it messed it for first week until i got hang of spamming keys on mechancial keyboard.
p.s. i got Corsair Gaming K70 with red switches. Its very nice build quality, with red only illumination (you can regulate brightness/turn it off), a metal plate finish (feel very nice) and its priced very nice. Before that i used Logitech G19s membrane gaming keyboard.