I've been a participant in the Seti@Home project for over two years. I started off using the graphical screen saver, but after a while I changed to the text client since it was marginally faster, but also because that way I could have several units of work "on the go" at once. This is very useful if you don't have a permanent ISP connection and know a unit of work is going to finish soon after you go to bed and you can't stand the thought of your computer sitting idle until morning. Simply download a second unit of work and run both simultaneously. The first unit takes twice as long to complete (since it can only access 50% of your CPU resources), but it still soon finishes and the second unit is still going the entire time until morning.
The only drawback to the text client is it's not as easy to check the progress of your work units. Even if you enable the "verbose" option, you still have to switch to each text window and check it in turn.
The Seti@Home Progress Meter (SAHPM) places a Seti@Home icon in your system tray that slowly changes from green to red as the work is completed. It can measure the progress of up to three work units simultaneously.