I did a test ride of the Momentum Transcend E+ today. It was definitely an interesting and much needed experience. My takeaway is that I just had poor expectations. I expected too much power from a mid drive bike, when in reality it wasn't that much different from the hub bikes I have tried in that aspect (much different on other areas!). I biked around town, tried flat surfaces with a mix of low and high assist, and tried a 10% hill on max assist.
In terms of the feel, it was definitely a pleasant and smooth experience. It truly felt like an actual bike, just stronger - much different than the hub bikes. Pedaling with 0 assist was doable on flat ground, but not a lot of fun. On assist level 1, it felt like a regular bike on flat terrain, but still had some drag. 2 and 3 were the nicest for flat riding. Going up the hill on PAS 5 still required significant effort on my part. I am 165lbs and very out of shape, so definitely worked up a sweat going up the hill. On stoplights, I understand the difference between mid drive and hub. The hub motors I tried would leave everyone else in the dust from a complete stop, they give it their all from the get go - I guess this is what people refer to as 'jerky'. The mid drive was much more gradual - easier than a regular bike, but more similar. Shifting was a learning experience - I had to fight the urge to shift while pedaling. I did that accidentally a few times and it didn't work. I had to stop pedaling so it would shift.
I tried a size large - I felt that it was leaning forward a bit too much for my taste. Nothing that an adjustable stem wouldn't fix and/or maybe different handlebars. The medium would have suited me better.
Carrying it up and down the stairs with the battery was a non issue. Very lightweight, very easy. I was afraid it would be difficult - not at all.
Overall this was a great experience. I now understand how it feels and have much more moderate expectations. I was a bit disappointed that I don't get a drastically better experience or hill climbing ability given that I am paying so much more. I can relate to
@Marrduk24 in the sense that in certain moments, I felt like the citibikes gave me greater assist. I feel that I really need to be smart about my gearing when using a mid drive. For hub bikes, you can use whatever gear you feel like to climb a hill, since it directly drives the wheel without any regards for gearing. I do get a more natural feel and better components/reliability.