I think for Jake it is a move that is no doubt motivated by a huge salary increase, as BT is spending a lot of money on sport and obviously wants to grow that side of their business significantly. It's what everyone does, so can't blame him for that, it is a shame though.
In the long term though, I'm not sure it was the best decision. Whether you like him or not, it was clear he was being groomed as a future lead anchor for BBC Sport. Just look at the Olympics, he knew well in advance he was going to be doing it and had a big role amongst their most seasoned presenters. That's not to say he couldn't come back one day I suppose. It must be a pretty big blow for the Beeb though.