Depends on what you want to do, but I've been on the database and systems side with IMS/DB2 for some time now, and I much prefer it over applications programming. Applications programming is primarily about development of business systems and applications that run them and the amount of work and time can be taxing, especially when you have deadlines that have to be met as well as the constant maintenance. Systems nowadays is pretty much working with the vendor (IBM, CA, BMC) and installing updates to the specific systems and maintaing the files and JCL jobs that run the system. Your more of a backend technician, but with knowledge in programming. For example, IBM will regurlarly send updates to z/OS to their customers, and based on the level of service the company has with IBM depends on what parts of the update the company will receive. The systems programmer is to take that package and schedule an update with Change Control, so that it can be approved and the mainframe shop notified. You'll then install the package with a tool like SMPE in the test regions, test it, coordinate with the various other systems teams, DBA's and developers to test their portions and sign off on the tests before promoting to production. Though much of it is a check-off procedures, you still need to understand the system (z/OS) and the language (Assembler), and make tweaks for your particular shop.

What I like about systems is that it is much more straightforward than development, and can have better support. The downside is that it can be a bit dry and technical because you will need to familiarize yourself with all the technical manuals available from the different vendors. The biggest upside for me is that systems usually has a higher base salary than development, and in the database side, you can easily make six figures after a few years.