What's the point in the slider? Just show all 5 variants at once.
Also, great idea with the "Keep track" button at the end. Registration (and therefore conversion) becomes a part solving the user's problem ("How do I keep track of my work satisfaction?"). If it weren't for the slider, I'd definitely click it.
I kinda like the slider idea. There's no need for me to see the extreme options, it's enough to reason about whether the default case applies - if not I can play around with the slider. Exploration versus direct information is an interesting UI aspect I haven't really given much thought until now. Too much of the former and your UI looses discoverability (e.g. Office Ribbons). Too much of the latter and you overload your users with information (e.g. Eclipse Toolbar).
The range of options that the slider offers is not equivalent to the options offered by just displaying the 5 variants - with the slider you can select a lot of values in-between variants.
Having said that, I'd prefer a keyboard-only way to do it too.
Developers also tend to spend quite a lot of time sitting at desktop-class machines with nice big monitors, because amazingly enough Emacs/IntelliJ/Visual Studio/whatever doesn't run on an iPad mini.
Thanks for your feedback. I must admit we did not experiment too much with different UI controls here. The continuous scale input with discretely triggered descriptors may be a bit odd to some - on reflection it is to me too!
Also, great idea with the "Keep track" button at the end. Registration (and therefore conversion) becomes a part solving the user's problem ("How do I keep track of my work satisfaction?"). If it weren't for the slider, I'd definitely click it.