I, as a Riese Muller owner, suspect depreciation would be very high as it is with all ebikes unless you can find someone who actually wants one. Its the same with high end cars.. The more you spend the more you lose!
I have just spent £6400 on a Supercharger, and would I buy one at 3 years old for 4K? Not Likely!
Everything moves on.. Just looking at the changes in my bike in just one year.. E-14 electronic gearing and Kiox.. so three years on anyone with 4K to spend with have so many options...
But, its not all bad although SW's comments about weight and battery life do hold water.. I have done about 250 miles on mine and am astounded by how light and menouverable it feels, the steering is light and I can almost ride it to a standstill without wobbling and the riding position is absolutely perfect, in fact it makes my old Scott e-Genius 910 feel heavy and cumbersome by comparison. I can ride it in eco on flatish roads where 2 % of battery took me 7.5 miles and my prefered EMTB mode usually shows me about 80 miles of range, but, Start climbing the big hills and the weight becomes very apparent with a 6 mile ride up ilkley moor zapping 10% of my 1000 watts, but the 15 mile ride home only took another 15% so it ballances out. ( I am riding wounded with a leg injury so not trying too hard..)
I would say get one bought and dont worry about selling it on..