Go with Ryobi Lawn Hornet built 1980. This machine was built to last. Maybe the reason why old Ryobi Japan lost the business and sold to Homelite because they built a units that will last for decades. I still have this units working. Obviously there's is no petrol Trimmer that will last without rebuilding the carby and replacing diaphragm and gasket. But mechanically I recommend the vintage Ryobi.

Cheers,
CM