I use a DL1608 when I run live sound. My PA is portable or certain clubs I will patch it in. Super compact and nice since you have tons of flexibility and all the fx you would need for just about any live mix (Compressor, gate, eq, graphic eq on outs, etc.). And for the price it is a steal.
However, it is much slower to move around on the interface compared to properly labeled racks and an analog console. So like monitor mixes and such do take a little bit longer. Or quickly dropping mic levels for feedback can take that extra precious 1-5 seconds to find. Mackie added mute groups, and views which help.
No bussing which is a suck, and no digital gain, so you have to set that at the board and use like a grease pen if you soundcheck a headliner and re-patch for openers. But the scenes help with other parts of that.
In practice, walking around the crowd isn't as nice as it sounds. Yeah it is cool to check the mix in different positions and make changes right there. Plus people oooh and aaah. But I find I still prefer having a home base mix position and I work from there most of the time. Plus the band expects you to be there when looking for you for changes to their monitor mix.
Not to mention moshers and roaming through a dense crowd with your relatively fragile iPad. It is just as easy to walk around and make small changes back at the board. Oh and my iPad 2 can easily run a 12 hour festival on a single charge which is nice.
I think Mackie's interface is the most intuitive and use friendly. Behringer's is a bit darker and more complicated and requires more nimble fingers. You can download them and play with them in offline mode before you buy BTW. But that being said, I am in line to get an X32 rack once they are in stock. My plan is to eliminate the snake so I an setup a mix position wirelessly. I also have wireless lights. Just need power for the board and charging.
For me really I make the compromise of quick action and paging through screens for the portability and not having to bring and hook up a rack of FX. And price, can't beat it.