I'll add to this, since I just had a pair of the ZLX-12p's delivered yesterday and spent a few hours at home with them at various levels. I should note that I'm not currently in a band and mainly play at home through a pair of Yamaha HS80 monitors, so I just needed an affordable set up for the occasional jam session.
First the not so good.... Seems like one of the units has a nasty buzz/vibration heard only when cranked pretty loud and brought about by chugging on the E string. This seems to be the same issue that Zentman noted in another thread, and I don't believe it is just the wire recall issue. It is coming from somewhere inside the back panel. I tried to dampen the panel with my hand while hitting the E string, but I wasn't able to eliminate the buzz, so it must be something resonating internally. I like these speakers, so I will be getting in touch with EV to see if I can easily do a local repair or if I should just exchange where I bought it. The other unit is fine, so I'm not concerned. I could probably open it up and fix it myself easily, but I'd rather not tinker with a brand new speaker and potentially void warranty.
Now that the negative is out of the way, I must say that I am very impressed with the sound quality and bang for the buck on these. I find that factory and personal patches translated very well with only minor adjustments to the low-end, which is probably more my room than anything else. I have these on the floor, so I set the location to "monitor." For guitar, I put them in "live" mode which sounded great and still had plenty of bottom end. If I were using them in a live monitoring situation, I'd probably roll off a few more dB on the lows, just to avoid any mud and help them cut even better on stage. I also put them in "music" mode and tested them out with a variety of music and they sounded killer....great clarity without ripping my ears with shrill highs. My wife and kid were out for the evening, so I turned these up louder and longer than I should have and was surprised and impressed at how little ear fatigue they inflicted on me. I really have no complaints about sound quality, other than they might not push quite as loud as some other options, but they sound great at volume and I honestly can't imagine doing any better at this price point. I probably didn't crank every last decibel out of these either, but I did have the input levels optimized and the master output at 0dB at one point. They go to +10dB, but I'm not sure how much of that is usable with correct gain staging.
In addition to the sound, I have to say I love the built-in DSP. The EQ modes are a nice-to-have, since we already have great EQ options in the AxeFx, but the metering was really handy for setting ideal input levels. Much better than guessing or looking at a clip light to see if you're clipping the inputs.
Though I'm curious to hear the more expensive coaxial options, I'm more than fine with these for my current needs (once I get that annoying buzz sorted out).