The new and hopefully soon to arrive Apple Photo solution should give Adobe pause. Hopefully it will be more geared at advanced to pro users but with a shallow learning curve for the beginner to novice that wants to edit photos.
There is no migration tool. The easiest and simplest way is to STOP using Aperture at 17:00, and at 17:01 use Lightroom to process your photos. The time is irrelevant, as I was using it to make a point, but none the less, keep Aperture on your Mac for historical purposes but process from the future forward only in LR.
I tend to buy the theory that Apple is losing its cool factor but more so that Apple realizes that their products are not as "cool" with the urban collective. For the most part Apple products are seen as products for white people, and Apple is seen as white company. Maybe Dre can change this.