I have been riding this bike for over 2 weeks now at our shop and have put close to 100 miles. I am really impressed by the build quality and bicycle-like handling.
I would say it's a biker's bike. It's very subtle and very different from hub motors. It's rated for 250W nominal and because of the dual chain rings, it has no problem climbing steep hills.
There are tons of user reviews on Brose here: http://www.pedelecforum.de/forum/index.php?forums/brose.53/
Compared to the Bosch batteries (400Whrs), these have 640Whrs. On assist level 2, I have gotten 65 miles at an avg speed of 18mph. For off-road, this is a great bike. I would not use it for commuting as it's limited to 20mph.
A friend of mine owns Pedego Ridge Rider, BULLS EVO E-stream FS 3 and few other ebikes. We were discussing about the differences between the Ridge rider and the BULLS.
He did post a very objective review here:
Ravi, I guess you put it well. A good bike for someone fit, or young, to ride. I am older. I rode a couple bikes with the E-rad kit installed (Bafang), one MTB 750w, one cargo bike, 1000w - that's what I think an ebike should feel like!
We also rode some Bosch powered bikes today, and even they were noticeably stronger than the Brose.
I think when a company like Bulls comes into the American market, and simply retains the 250 watt, anemic limits, of European bikes, they are missing an opportunity. I know their sales will probably be light and they probably can't afford to provide a separate motor for the American Market, but I hope they will be able to sometime in the future.
In the meantime they can appeal to riders who want more of a workout, but that's not me.