I purchased a Wisper 905 Torque Crossbar 2 months ago, after owning a crank drive Cube. The Wisper has a rear hub and mine has the basic 375Wh battery. I shall be posting a full review in a few weeks, but a 905 Torque might be worth your consideration. Cost was just shy of £1500, but you could get a larger capacity battery for around £1800 total. I have been delighted with the bike, running it on assist level 3 with 4 and 5 reserved for steeper climbs. Its not the 'shove in the back' assistance I got from the Bosch CX, but is nevertheless very noticeable and gets me and my pacemaker up 12% hills without any bother. Build quality is excellent and customer service great.