I don't have experience with C4 or Savant so can't compare them. For what we have done with Pyng (Audio Distribution, some lighting control, some HVAC) We haven't had any problems with it, but haven't tried to do too much.
Setup is fairly quick for a 4 or 6 zone audio system, including 6 or 7 CLW-DIMEX lighting keypads (maybe an hour once all devices are installed). I don't have experience with 2.0 yet but with they Hub you are limited to what Audio sources you have control of (basically CEN-TRACK, Sonos and Autonomic). I haven't done a Sonos system yet but I do have one coming up. Have done both CEN-TRACK and Autonomic and haven't had any issues with either. Although I did read that the new MMS-3e and MMS-5e are not compatible with Pyng (I have used the 1e and 2a without problem).

The ability for the home owner to add/modify scenes and schedules is a huge plus since Crestron never allowed for this without major custom programming.

There are a few quirks/limitations that I have found while doing the above setups:

1. You either need to program each wireless keypad as you add it to the system or write down the SN and what room and light it controls before you start acquiring or you will have a huge list of wireless devices and no idea what each one is for. If you do that then you have to remove all the devices and start over again.
2. The Thermostat screens are a little confusing (using an iPhone) in that it is the only device that has a swipe function to get to the set point adjustment screen. All other devices require a button press and drop down page where you can select the screen you want to see.
3. There is limited programming that can be completed prior to going to site. You cannot build a 4 zone audio system with wireless keypads without all devices connected/acquired to the Pyng Hub. It would be great if this ability became available (I'm sure it's in the works). Right now you can only program a wired lighting system and I think that is still pretty limited to only allowing to setup the CAEN enclosures and modules, doesn't allow you to add keypads (not sure how it determines the ID's for the lighting modules either).
4. Limited keypad button programming options, Double tap, Press and Hold options are not available.