I can't fault my 650.

I looked at the Transalp before buying mine and it's a good competent bike but the 650 won the day because of the extra bhp, it's lighter, the seat height is lower, if that's a factor, and has a tank range of up to 250 miles. Mine averages 72 mpg no matter how I ride it. Can't complain about that and there aren't many out there that can compare with it. Plus there's a lot of extra stuff to put on it if you want to.
I should also add perhaps that my local BMW dealer gives a excellent service experience - odd thing to say maybe, but it's so much better than going to the local Japanese dealer - you just feel better looked after though you're probably not!! (Maybe it makes you feel better when you're paying for your service

)
I guess it's what suits you best and what price you can get one for at the end of the day but if I was going to change my bike I'd go for another one.