It's one thing to love what the Mackie DL can do and then there is the matter of measuring it against what YOU need to do. If you're not one of those people who live and die by your iPad, or own multiple tablets - you'll also eventually resell it to the first interested buyer.
Anything that disables your iPad disables you're access to these kinds of tablet based mixers. So, in addition to the mixer - you need to buy a second iPad as backup or perhaps get used to using the tiny screen on your smartphone.
A secondary live surface is critical. Imagine you're in the middle of wedding ceremony, and you drop and break you iPad. The mix will continue without interruption but, when it comes time to un-mute the reader's mic, or bring up the level of the recessional music - you won't be able to do it without an active iPad or Android already synced and running with your mixer. You can build your my such that all channels remain open at all times, however not all situations are going to allow for that, or make it desirable. .
A lot of portable digital mixer's have this requirement, but some expand your options to include a wired PC along with more sophisticated offline editing and setup.
One thing that QSC did right in this tablet class was too include a tactile interface on the Touchmix series so that you can control it even without tablet. That's not only a backup to you tablet - but, it also forgoes needing connection to a PC. The downside is there's no offline editor, but once you've saved your presets to the unit they are there for you to recall at any time.
