I've also found the lack of parametric polymorphism a huge pain point. Type safety is constantly sacrificed to allow for code-reuse and nicer APIs, leading to really awful code using type switching at best, inscrutable amounts of reflection at worst. This seems to plague the Google developers as well, just look at the Go App Engine APIs.
I concur. I was in a similar situation at the beginning of the year. Started a new company with a couple friends, and it's rekindled my passion for programming and forced me to grow not only as a developer, but in numerous other areas as well.
The challenges associated with starting a new company will be varied and entertaining, drag you outside of your comfort zone and demand the most of you.
Build something cool. Build value for yourself and others. Find other people that believe in you and want to work with you. Very little is more exciting or rewarding.
Not much different, really. The biggest practical difference is that Python generators implement the iterator protocol which means it's possible to easily iterate over them with for loops, etc.
I have experienced OSX's "swappiness", having gone as far as disabling dynamic paging in an attempt to avoid it. Upgrading memory was the only real solution. A little bit of research would reveal a lot of other people have run into the same problem, you aren't alone at all in that.
I split my time between OSX/Linux and it's pretty obvious to me that Linux is vastly superior in terms of performance, in a wide-range of scenarios. I prefer to use Linux on older and/or memory-constrained systems.
Using jslint has saved me a lot of time (I lint everything on write in vim using syntastic). Syntax errors can pass silently leading to difficult to find bugs. Using strict mode helps with this as well. I have also started to prefer Chrome for client-side JavaScript development, it seems to let less slide than Firefox, although Firebug is pretty dang nice.
I'm not about to remove Gentoo from my older servers, but I'm probably never going to install it again. Not having to compile everything is a huge win. The Arch build system is fantastic. It's easier to create/maintain your own packages. Arch's packages seem to be of higher quality, and more frequently updated. I've found the last few months of using Arch to be completely delightful.
I prefer the crippled lambda. If you need more than a simple expression, you should write another function anyways. The restriction leads towards easier to read/maintain code.
...reads great in my opinion. Surprised no one else has brought it up.