If you are powering a relatively light load, the belt system will do a reasonable job... as the load gets heavier and mechanical accessibility reduced a proper clutch is the only way to go...
There are a lot of 'lever' systems out there, just treat it like you want it to last, ease the system when starting up... remember the laws of motion apply... things at a rest tend to want too stay at rest...
What mower did you get? :smile:KennyV