I introduced the T-slim to our endo (pediatric) for the first time last year after I stumbled upon it online. She did some research, and gave us the A-Ok to give it a try. Since then, she is promoting it equally along with Medtronic, Animas, and Omnipod. We have had zero issues with the T-slim and my son (age 12) has been using it one full year. It's sleek design/touch screen make it very appealing for anyone (especially a boy his age.) I highly recommend it and I am sure Dexcom/Tandem will end up with an "all-in-one" device soon. My son also wears the Dexcom.
We had a few issues with Medtronic (it was far from perfect) and I can't assure you the T-Slim will be perfect either but so far we are very pleased.