My partner had an Amego bike. Rode it for 2 seasons and sold it earlier this year. It was a better bike than the DJ ebike. Better gearing, noticeably so. He sold it only because he felt like an Uber delivery person as they all rode the same bike. I went for this one due to the fat tires which at that time weren't as commonly sold as I see them this year.
I hope that the quality would be better with a company like Trek, Giant, etc? One thing I hated about the DJ bike was the gearing. It was fine pedalling uphills and different terrains but on a long piece of flat land where you pick up speed, the gearing was terrible. Your legs would spin around too quickly. Although in my case I rarely was on such land, when I was, I stopped pedalling and just used the power. That same issue took place with the Amego bike but to a much much lesser degree.
I would hope that with Trek or other such companies, at double the price, plus, that issue would not be happening?!
In my case, I went with DJ as I wasn't sure I would use this bike so I didn't want to lay out $5,000 unless I was sure I would use it but I would want a test ride first on my next purchase.