First, let me point out the downsides:
1. Yes the frequency range of one mic will be out of spec - so you could not use that one, and buy a second set and only use one of the others too, and still have a heck of a deal.
2. I can find no way to have them power on when power is applied - which means you will have to power on your rack and then power on each of these receivers manually (unless I am missing something)
3. They are not rack mountable without placing them on a rack shelf and using double side tape
4. The antennas are not meant to fold flat for easy storage in a gig bag, you would be best to take them off when transporting
5. The antennas are on the back, so if you do put them in a rack, they will be behind a bunch of metal that will reduce their range
6. On a dark stage, you cannot see the polarity, so you might have someone put the batteries in and not have power and have to do it all over again - also, some battery brands are a little too snug, like Kirkland (Costco) so they are hard to pull out once you put them in.
Okay okay - so what makes them great then?
1. They are built very well. As others have noted, they are heavy in your hand, they feel about as good as our Sennheisers, like a real piece of pro equipment. While we have not dropped one, I feel like if we did, it would not shatter into pieces like other budget mics.
2. They are good looking and when mixed with our pro-level gear on stage, people cannot tell we didn't spend a grand.
3. The range is more than adequate. We have not found a stage that is larger than the coverage - however, our receivers are in a rack ON THE STAGE, not at the back of a sanctuary or something.
4. The infrared frequency setup is instantaneous and accurate - it's never failed to work correctly, unlike some other brands, even higher end gear.
5. The audio quality exceeds all expectations. I record every show, and that means I have isolated audio from each mic and member and can easily compare a Sennheiser wired to a Sennheiser wireless to an SM57 to the Innopow. And guess what? In almost all cases, the Innopow sounds superb! I'm not yanking your chain here, on quiet to loud songs, they are pretty amazing. And their pattern is pretty good, so they don't pick up too much noise like drums, and they are not bad about feedback. Like most mics, if you move up on it tight, bass response can be amazing. The only weak point is that if you have someone who belts AND cups the mic, it will distort a lot easier than a 57.
6. The price is a big point for us because while we have 3 higher end Sennheisers systems that were bought for key members of our band, other members have come and gone and others have made no investment - these are perfect for them and for guest mics. It's hard to justify buying everyone else's gear, so they get what they get right? At least they get a very decent mic that they are not embarrassed to be behind!
There you go, 6 pros and my 6 cons.... The pros far outweigh the cons for sure.
And I have a follow-up after purchasing my first system in February, I bought a second system after one of the two mics died.... Not sure what happened, it wasn't dropped, but the batteries would heat up red hot as soon as you would turn it on.
Why isn't this a "con"? Because everything has troubles - my expensive bass amp is dead, died at the same show!
Rather than cry about it, I ordered another set of mics. I mean, that price, right?
But wait - there's more... On a whim, I contacted the seller and told them what happened, early on a sunday morning after our gig... and by Monday morning, they had replied to me and said it was probably a solder ball on the circuit board - and they sent out a replacement....
I had a replacement from them in time for rehearsal on Wednesday.... Used it at Friday and Saturday night's shows and sound as good as ever.
Meanwhile, my expensive bass amp is in the shop until the middle of next week before they can even look at it......
So, it's not Shure or AT or Sennheiser, but I would not (and did not) hesitate to buy again or recommend to my friends.