Before starting to use these tools, you first need to spend a few minutes setting up the different activities you want to track. Whereas Slim Timer uses a very simple list, activities on Paymo can be further sub-divided into projects and again into clients; there was also an invoicing facility which would be useful if you have to submit timesheets and charge for your time.
As far as using the tools, it's a case of selecting the appropriate activity and starting the timer with a mouse click. When you want to stop timing, you just click on 'Stop'. I liked that with Slim Timer it's possible to stop timing one task and start timing another with a single click of the mouse. Paymo takes a few more clicks when you wanted to change over as you have to stop, select project, select activity, then click to Start. Both timers run in the background, ie they're not visible on screen until you want to see them. Paymo has an annoying pop-up message if it doesn't detect any computer activity for a few minutes - it made me feel guilty if I wasn't typing all the time!
If you forget to start timing an activity or want to include time spent out of the office in a meeting, both tools are easy to edit.
Slim Timer's reports are very readable - giving me both weekly totals and daily breakdown. Paymo's colourful graphs looked impressive but the more detailed reports lumped everything together for the week which I found less useful for my purposes and not so easy to interpret.
My (very non-scientific) trial was undertaken to find out what activities I'm spending most of my time on. For that purpose Slim Timer was perfectly adequate and marginally easier to use, even if it's more 'basic' in appearance. If I were tracking lots of projects for different clients, then Paymo would have the edge in terms of extra features.
Have you tried out any online timers lately? I'd love to know!

