If the C7 has internal Z devices then it won’t work for me. 
I use my USB sticks ‘remotely’ on extension leads.
Last year, I briefly tested a couple of hubs with UK internal z-wave. They worked well before I ‘bricked’ them (not my fault!)
I still have two UK/EU C5’s sitting on my desk here as ornaments
Andy
Unless the new device comes with a lot more horsepower (cpu. memory, iops), new capability, or stronger radios/antennas, I doubt I'll be too interested. 
Repackaging the existing, like the C4 to C5 basically was, just doesn't interest me.
Until the hardware is more resilient and capable than the RPi 4 I use for HA, it is going to be hard to convince me it is a step forward.
You pretty much need all of those for your 70 messages-per-second MQTT bridge project.. 
I think more processing resources are about the only thing that would entice me as I am pretty well built out in terms of hub infrastructure.
I've tamed that down to something more reasonable. 
Although in my defense, I'll point out that an MQTT broker even on an rpi3 can handle thousands of mqtt messages per sec...
So in terms of MQTT 70/s isn't really a lot. Too much for HE though (although not for HA interestingly enough... Thus bringing the conversation back to hub resources. ).
It can probably hit 10k if the app is multithreaded/multiprocess... But I agree 70/s is high for the model in which the platform is built upon, but in the grander scheme, it's not all that much.
... and the potential goodnesses a C-7 hub could bring... 
I wonder what the timeline is of the new C7 unit and if it is for USA market. I'm on the fence if I should get a 2nd unit to put all of my Lightify lights on to prevent the random drop outs I've been experiencing (4 devices in the past 3 days). But would had to get a second current unit if a potentially new-and-improved version is on the horizon.
FWIW, the difference between the C-5 and C-7 appears to be in the z-wave daughter board (as pointed out by @Ryan780). I do have an HE for my Lightify bulbs and strips. No issues in several months. For me, it was cheaper than replacing the Lightifys. And HubConnect makes all that transparent for my rules.
Thanks … going off track, but what is the benefit of using HubConnect vs the built in Link to Hub/Hub Link app? If instability continues I may have go the route of getting a new hub which as you pointed out is significantly less expensive than replacing all of my Lightify lighting!
These two posts by @csteele and @bertabcd1234 answer that more proficiently than I could hope to:
Thanks … I'll check it out.
Just realized based on another thread....the change in Z-wave daughter cards might be to introduce S2 support for Hubitat!!!
The one about about Aeotec Range Extender 7?
Yeah, I happened to read this one first and when I saw the question about S2 for the RE7 that got my wheels turning. According to a post by Bruce, it wasn't just trivial change and involved more than firmware. So...it's possible they had to change hardware. But this is all purely speculation.
While we're all doing that, let me throw this out there. I remember reading that implementation of S2 is required for z-wave certification. So, a 700-series controller would kill many birds with one stone.
If the hardware change was required for S2, that would also mean that the C-5 hub most likely would not support S2. As far as C-4, I've not looked at whether the stick supports it, but that would be up in the air.
If all this is true then I would expect a true back up to be in the works soon aswell? I know they have mentioned that the background work is being done 
. So they may announce the 2 at the same time, it would certainly help with people making a decision to upgrade if the swap was straight forward. 
From what I know, S2 can be implemented in the 500 series chips. There's not a hardware limitation there.
The 700 series just has better performance for range, speed, etc. Probably handles S2 better, and maybe that's why some companies are waiting to implement S2.
For Example: the Zooz ZEN26/27 switches implement S2 on 500 series silicon. I think Schlage's Zwave Plus locks do as well.
Fibaro will use 500 series chip in the newest HC3 hub. That means they will not introduce 700 series chip in the next couple of years.
Download the Hubitat app
