They use the same code base, according to @dan.t There's no feature differences, they just gather Hubitat data slightly differently.
Dan and I have settled upon similar advice regarding the choice: If you have HubConnect already, then another Instance is simple and easy.. and familiar. If you don't then MakerAPI is the clear choice. I have both installed in my development environment quite often.. lots of flipping back and forth in that space 
and I can't tell any difference.
Happy Sunday to all!
HubConnect 1.6 has been released!
What's new?
Admin: HubConnect will now delete virtual devices from the remote hub when they are no longer shared. (Note: device deletion may not be successful if remote device is still in use by other apps)
Admin: New "Restart HubConnect Drivers & Services" re-initializes a single, (or all) remote hubs and re-establishes Websocket connections.
Core: Added support for multiple instances of the HomeBridge Remote Client neccessary to work around the HomeKit limitation of 100 devices per bridge.
Custom Drivers: Updated navigation for custom driver section of HubConnect server.
Custom Drivers: Reset Custom Drivers now prompts for confirmation before wiping out all custom driver definitions.
Custom Drivers: Added garbage collection to custom drivers on server instances to remove old device selectors when a custom driver is deleted.
Custom Drivers: Added many additional device capabilities to custom drivers for device selection.
Custom Drivers: Driver definition form displays fields only when they are needed and in the correct order.
General: Split HubConnect utilities into separate pages (Utilities and Reports) for better navigation.
What's Fixed or Changed?
Admin: HubConnect Server no longer re-initializes all remote hubs when pressing Done to exit app. (Hitting Done when prompted to update still does).
Admin: Fixed technical support report to be more resilient to communication failures for remote hubs.
Core: Updated websocket parsing to prevent multiple duplicate events from firing on HubConnect virtual devices.
Custom Drivers: Devices using custom drivers correctly populate the latest values of all defined attributes upon initial creation.
Custom Drivers: Fixed Remote Client custom driver garbage collection that was in some instances causing device selections to be lost.
Custom Drivers: Fix for Driver Builder to properly process selector lookup against the correct attribute.
Updated Drivers (Hubitat):
None.
New Device Drivers (Hubitat):
Updated Drivers (SmartThings):
None.
New Device Drivers (SmartThings):
Important Links
Installation Instruction (New Installs)
Thanks for the update.
So far, so good.
Installation Instructions, Videos and Import URLs are all found here as well:
Just tried to do the update, must have missed something. Any ideas on what to look for?
This is on the server hub...
Only 1 remote hub and it's another Hubitat
System Version Report showing everything is up to date (all green).
Tried rebooting both hubs too.
Thanks
I usually get that when I copy the Instance into Server. Look at App Code... are there two with the same name?
I also used all imports (prefilled in) from last time.
Edit: just went and manually entered in all the import URL's again with same result.
First thing that I would try is to delete the HubConnect Remote Hubs then go back through the key exchange process between hubs.
If that fails DM usa technical support report.
Will I have to setup everything that is shared (devices, apps, etc) all over again?
No, it's a benign process.
Nope.. It will just make sure all connection settings are correct and cause the virtual hub devices to get re-created.
Thanks for the quick replies, just to be clear what exactly do I need to remove? 
Server side or Remote Side and what's it called. I really don't want to mess this up! lol
I just tried it. It didn't stop the error.
We're talking about -> Devices --> HubConnect Remote Hub (1 or more)
I usually go into Devices then click on the Type column, then scroll down to what I'm looking for, which I did above.
--
While you're in there..
Watch the Current States, EventSocket Status.. and click ON.. you should see it go through the connection process.. and end up at "connected"
With v1.5 (and now 1.6) there's a Hub DEVICE at each end. Wouldn't hurt to click On in the other Hub too.
I think it's only right and proper to comment about how the upgrade impacted me for the 1.5 to 1.6 upgrade.
IT DIDN'T. 
The reason for my comment is the last 2 upgrades caused major issues.
I did a complete delete of everything and started again with the 1.5 update.
I think this means that it was probably user error (ME) with the initial install.
Thanks again guys.
Where do I find it?
Nevermind, found it. Sending it.
Is there any way to find out what device the logs are talking about? My logs on the server have a bunch of these entries in regards to one of the client hubs.
Something you selected inside your "Office" hub got deleted on the other Hub... probably just go into the Device selection menu again, deep enough to see the devices and then DONE all the way back out. It will recreate any missing. Watch the Live logs on the other hub and see if there's an error building them.. such as a missing Universal driver.
HubConnect Server --> HubConnect Reports:
Direct Message/Private Message it to us. DM/PM Don't publish it here 
Just tried that. Went in to share devices to the server, hit done to get out. Live logs on the server gave me a bunch of "exists... skipping creation" but then a few more "Device Not Found".
Download the Hubitat app
