I dont have the luxury of 120' lines to slow the kite, so unless I ride the brakes I will develop pull in a great hurry and run out of window fast. I have many days where one more level of venting would be most welcome and I would not be getting sand blasted.
Yes,I own a full B2, Pro and Polo set and have flown them all to their upper and lower limits.
I think the B2 is more of a solo pilots toy since the 1.5 platform is far better for team... And most people here seem to not fly solo that much. That may partially account for the lack of feedback... That and people are (wrongly) afraid of its 'speed and twitchy' nature.
I originally thought I would like a B2 Xtra vent, but I find myself far more drawn to the 1.5 platform because it's just a better all around package. I still like my B2,but given the choice I will fly a 1.5 based setup.
The fact that people are actively using a B2 for more wind than an Xtra can be comfortable at, people keep asking if the Polo or B2 takes more wind, that people want an Xtra B2 or an Aldens Vicky rev... These things all tell me that something more than an Xtra is being asked for