I just sold my Bernina 440 QE with BSR foot. It's a fine machine but I had lots of tension problems, specially with FMQ! I rarely used the BSR foot as it's huge and it's hard to see where you've been and where you need to go. Backtracking is very difficult with the BSR, at least that's my opinion.
I used to sew a lot of clothes on my Bernina but not anymore so I sold it and I'm buying a Juki now with more throat space.