We used it in early May and had a positive experience with the service.
If you wish to handle your own luggage, just leave the yellow Disney tags at home (you will still need to pre-register for the service), collect you own bags and you can still ride the DME bus. ANy bags you have with you will be stowed under the bus you ride on and you'll just gather them upom arrival at your resort. (They handle the carry-on bags in this fashion already.)
On the return trip, it works the same way. Our airline was not a participant- so we had to check them ourselves at MCO.
We found the arrival service very convenient. Our bags were delivered to our room (it took almost 4 hours), but we had everything we needed upon arrival in our carry-on bags- so there was no inconvenience having to wait.
By October, I expect that the initial challenges will be smoothed out and the service will be running very smoothly, but there would be no problem to handle your own bags if you wish and still take advantage of the free transportation.
Enjoy!