I have three ebikes and they all work well. The Optibike is the 'Lotus' of them all -- It is the only high performance ebike I’ve found of in my three years of research. There are some ebikes that are practical transportation and many that are made to be low cost but are not durable.
If you just want to go down the road and a $1500 Chinese bike makes you happy, go with it. If you want to ride fast on or off road with 20 ah of 3 year guaranteed Lithium, top of the line brakes, suspension, wheels and tires then get an Opti. The EMS E+ is a good bike too at half the Opti’s price but it has 9ah to the Opti’s 20 ah of battery power and it has standard components to the Opti’s high end shifters, forks, hubs/wheels, tires, seat and etc. The Opti being under 50 lbs and having the power it has is unmatched -- I've been on lots of ebike forums for several years and own three of the most common ‘good’ ebikes. Opti's claim is true -- it handles and performs much better. Plus, I simply flip the switch and take off -- no plugging in or taking battery packs off and onto the bike. I can take it up stairs, flip it over for service or put in in a car by myself – 50 lbs for Opti and 70+ for most others. Light weight user friendly engineering costs more.
I use my Opti hard as I ride over Mt. Tam to work = 15 miles and 2000 foot vertical climb. There is no other ebike I know of that can do this at all AND in less than an hour AND me with no sweat! I've spent $ thousands of dollars on Lithium packs as have the guys on my other forums and these packs died in a year. Now I have 3 years guaranteed in my country, in the town I went to college in, Boulder, Colorado. My ride is extreme being over a mountain. If you don't need all that there are some other good ebikes but no other can provide this level of performance or even get over the mountain.
It's hard for any ebike to compete with Opti for off road -- having 20 ah built in, 800 watts of power, superior suspension, brakes and shifters at under 50 lbs allows them to make their claims -- it's all true. The E+ is a quality bike (I have a Tidalforce = same bike) but is a hard tail weighing 70 + lbs and with standard components. The E+ is silent where the Opti has a small buzz/whirring sound from the gears -- But the gears make it more efficient as it uses less power to climb hills. I do like the silence of hub motors.
I built another bike with a crystalyte hub motor. It works well but can’t get over the mountain and one MUST be mechanical to get the whole thing to work. Many have had controllers burn out on these and etc. I tinker and check it regularly (which I like, it's like my Ducati) but with the Opti I just get on and take off -- like my BMW motorcycle with 100 K miles -- the Opti runs like a top.
If you have other questions let me know and we can talk on the phone or you can see it and ride it. The Optibike is quite the exciting machine!