I bought 3 KncMiner Jupiters that the end of 2013 that provided a nice profit.

Those were the good old days when you could ROI in ~3 months and actually mine a decent amount of BTC each day without having to consume an insane amount of electricity.

The downside was that hardware purchases back then were a major gamble. No in stock ASIC hardware was available, so pre-ordering was the only option, and many hardware companies either didn't deliver or delivered very late.