I've got a Trek Powerfly LT8 and I love it. I've ridden a Levo and didn't like it, but I think I'm the only person on the planet who doesn't. I do like The Kenevo though, so there's still hope for me...
You should bear in mind that the weight limit for the Trek is 300lbs total weight, that's bike, rider and riding gear.
The Levo depends on which model but it's 300lbs at best;
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If the Trek is really half the price, I'd be jumping on it immediately.
There's no drag when freewheeling, only when pedalling without assistance. At slow speed it's like riding with the brakes on until you're doing 6-7mph then it's not too bad. Over the speed cutoff it's more noticable when in the higher assistance modes as going from 300% assist to none is a bit of a shock (Turbo) but 50% to none is barely noticeable (Eco).