Typical lease costs for the less expensive EV cars - Spark EV, Fiat 500e, Leaf S:
* $7200 payments = $200/mo * 36 months
* $1000 down payment
* $1200 power = ~300 Wh/mile * 36k miles * $0.115/kWh
* $400 1 set of tires
$9800 after 36 months
+ insurance, maintenance, cost of installing EVSE (often can be rolled into the monthly payments)
Typical 3 year costs for a 2013 S ZF8.5, assuming the same 36k miles:
* $14000 base price
* - $1400 10% tax credit
* $600 power = ~150 Wh/mile * 36k miles * $0.115/kWh
* $1000 tires = replace rear every 6k, front every 12k
$14200 after 36 months + owning the bike
To break-even cost-wise, you have to ask whether the bike is worth $4400 to you or a potential buyer after 3 years.
The EV car leases are a pretty great deal for consumers, especially as it pushes battery longevity risk back on the manufacturer. I don't think we'll see a lease deal like this from Brammo or Zero .. first because motorcycles are rarely made available to lease, second because their distribution network is still very small. I think they COULD offer an optional battery performance guarantee at relatively small cost.
In the end, the cost is fairly similar. A less expensive bike - eg Zero XU - could swing costs back in favor of the bike ($11k after 36 months + owning the bike), provided that it meets your needs.
I think it's close enough to say that the costs are comparable, and you should buy what you want to drive or ride.