Yes I use them with my company. The PTT is good and easy to use. The interoperability with the radio system is done by a suitcase Gateway/hotspot. The suitcase come set up head of time for one of your radios, can either be a mobile or a portable. Just plug and play. If you're going to have this set up at your Dispatch Center that's easier add on with the Gateway. The one thing I liked the most everybody with tango is great to work with. My sales/account rep will be in Jersey at the end of October, shoot me a PM if you want me to set him up with you.
The problem I had with Tango Tango (other than the astronomical price) is that the app is very invasive. I would be doing something on my phone and it would get this authentication pop-op that would take me right out of whatever I was doing. Sorry, that's a no-go for me. Plus, honestly, you can download Zello (for free) and use a similar gateway for radio interop.
I have never had that problem with with a "authentication pop-up". As for Zello yes you can download it for free but to use a gateway for radio interoperability you need to sign up for Zello Business which is $6.50 a person for a yearly subscription and $8.00 per person for a monthly subscription. We were using that before tango tango. Worked ok with analog radio systems, i would say 7 out of 10. Was horrible when used with a p25 phase 1 trunked system, and could never get it to work with a p25 phase 2. We have used tango tango with the mobile set up on every system from in the open analog to encrypted p25 phase 2 with zero peoples. But thats just my two cents.
Because Zello actually tracked me down when I did the samething on the free side. Was informed by a nice cease and desist letter from their lawyers. So if you have been doing it congratulations on not getting caught. And I hope you never do.