I have personal experience with (4). I work for a company that creates systems that are used on oil rigs. I came about this job in a round about way. I used to

I have personal experience with (4). I work for a company that creates systems that are used on oil rigs. I came about this job in a round about way. I used to work in SF at a big name tech company, but I'm from a small town with no tech community whatsoever. My parents got sick, and I wanted to live closer, so I made the move home to support them. Found this job though connections and here I am. The systems we create are complicated and require automation (PLCs, embedded systems, PCs) to function, so the company requires programmers. The money is fantastic for two reasons: they have a really hard time finding people and money for oil companies shoots out of the ground (most of the time). The work is different from most systems someone would deal with at a startup. The systems range in age from new to 20 years old. Object oriented is a new and scary thing. I write and debug a lot of pascal and C. Also do a lot of sysadmin work on ancient systems, token ring networks etc. The biggest difference however is work environment. Most rigs have an absolutely awful (think dial up) satellite internet connection, so there is no remote work. Everything gets done on site. This leads to a lot of travel, which is where you make the big money if you are willing to do it. The work environment is a lot different from a startup: Folding chairs and a table in the corner of a room if you are lucky, sitting on the floor if not. You get to see some interesting and scary parts of the world, police escorts from the airport, body guards on the way to the rig in really bad places, which can be very isolating as well as traveling for months at a time.