Primus has been designed with the first time builder in mind. It has big cogs which means the tolerances are not as strict as with a small clock. Instead of 4 cogs for the hour hand it uses a daisy wheel, which is a lot easier to make.
Primus also has a deadbeat escapement, which is very accurate and easy to setup.
Despite it`s simplicity it is still a fully functioning and accurate clock, and runs up to 3 days between winds, and with its straight up straight down elegance it will fit in anywhere.