The 658 is a capable bike. Stock its a little funky, with way to long a wheelbase IMO at roughly 62" for its low height.
For those that understand low rpm torque, you can drive the 658 off the bottom.
It is deceivingly fast. Faster than my Triumph Scrambler and faster than my friends 1200 Guzzi Coppa Italia. The Guzzi whoops on my Scrambler.
I bought mine because its the lightest twin cylinder street motorcycle available (originally stated at 377 lbs dry, although they bumped up the weight spec).
The 658 is a good candidate to build up.
Put an 800 aftermarket shock on and work the front to an equal height (various ways) and you have a tall-ish, light-ish adv touring steed with 19/17 tubeless wheels.
A nice combo.
I just did a 3000 mile + trip on mine. I carved the twisties, ran dirt and got up to 62 mpg. A great adv tourer for me.
I think the 700 is a good looking, classy upgrade to the 650. Wish I had one.