2016 Turbo SC (coming in September) has has a 500W nominal GoSwiss drive. This is, I believe double the existing wattage. Other changes include a much larger battery (still nicely integrated into the downtube) 817KW I believe, and has added AN+ support to the display/controller so you can now wear ANT+ supported devices such as a heart rate chest strap monitor. Any specialized dealer should be able to give you detailed specs and discuss differences.
And its the same price as the current Turbo S......
Seems like an amazing ride. I'd buy one if it came with a front suspension. The 2016 Turbo X will have the same 250W (nominal) motor as the 2015 model did, and that's too anemic for my tastes, though to be honest I actually haven't even ridden one yet, so perhaps I shouldn't make any determinations without trying the thing out first! ;-)
I have the MY 2013 Turbo S. It has quality components, for example:
derailleur is SRAM X0 (10 speed), works like a dream, Magura MT Carbon hydraulic disc brakes are very powerful. Motor is a Go SwissDrive 250W with 342 Wh LiNiMnCoO2 battery. The 2013 also has ANT+ support for, e.g., heart rate belts. The biggest advantage of the new version would be the 691 Wh battery, but because the 2015 Turbo S model has a 500W motor the advantage of the battery size is eaten up by a more power hungry motor. Supposedly a more powerful motor means also more drag from its magnets when riding without power. I think the 250W motor is enough power for achieving 28 mph, so if you can get a MY13 for a good price you could still buy the new 691 Wh battery (~800€?) with the price difference and have nice range. With the 250W motor and 691 Wh battery 50 miles should be achievable in 30% support mode. The new models come also with a 42V/4A charger, so the charging time should be about double (5-6h) compared to the 342 Wh battery. As for estethics, in my opinion the MY13 display and power controller are more nicely integrated than the newer models with joysticks. One of the biggest cons for the MY13 is the lack of chain guide, which at least in my bike results in chain jumping off of the ring constantly when riding hard over bumps etc. But this is solvable by installing a narrow wide chainring.
Thanks Marko. I have a to budget around $4000. USD. So a new Turbo S is out. Sounds like a 2013 S may be the ticket. At 6'4 and 230+ I need to try it on a hill. They have an xl so hight should be good. The others choices are a lightly used 2015 Stromer ST1 Platinum or Easy Motion Nitro City. A tall speed pedaled with integrated battery. I am leaning towards older model or gently used - most value for money.