Not all k pouch surgeons believe that the BCIR is better...from the ones that I have spoken to, most think that it is good and has some very good points (some of which are worth copying) but not necessarily better...just different and slightly more complicated to make.
I have never seen studies (never looked for them either) but they have mostly the same long-term outlook.
I would talk to the surgeon and see what he has to say and then speak with Susan Kay over at BCIR and compare notes,
In my case, beyond the medical considerations and because I was paying out of pocket (and am still paying & years later) It was a financial consideration too. BCIR cost, at the time, around $130,000.00 if I remember correctly whereas the K pouch was done in a public teaching hospital and cost me about half. I also had more freedom with my k pouch surgeon on length of stay in hospital and post op follow -up.
The final deciding factor was that I had where to stay for the k pouch but would have needed book hotels, flights etc for Palms of Pasadena.
Maybe money shouldn't be a consideration when choosing your medical care but it is for many of us.