I don't notice anything unless I have my machine doing some crazy stuff. That being said we haven't done any real performance tuning yet. Out of curiosity what macbook do you have? I run one of the 2011 airs.
I have an old 2009 white plastic MacBook, running Mountain Lion. This is definitely an underpowered setup given its age, but I generally feel that it is fast enough for the programs I use, including Sublime Text 2.
I've had the typing lag feeling with Coda 2 before, but that is to be expected because Coda is such a bloated piece of software with so many features, trying to run on my old MacBook. But I guess I expected Light Table to be a lighter piece of software like Sublime Text 2, so I was surprised to find that when typing in it I felt the same lag as I do when typing in Coda.
