I have been running it on an MR55 and MR56 for a month as part of the MR29 early access program. As a note, I have not seen either the 3rd or 5th known issue. The others would not have applied to my configuration anyway.
It would be good to know exactly what the 'enhancements' are to client balancing, band steering and mesh networking...for example, for my clients, band steering has not previously been always reliable
It is a new set of algorithms that at the moment are simply meant to be more stable, but are being developed to be more active. I normally turn client band steering off, but haven't had the usual issues with it on when using 29.1.
FWIW I'm noticing 29.1's proactive steering being more than just at association can cause a lot of client bouncing between APs if the AP steering is incorrect.
I have a space in my home where the AP strongly believes it's appropriate to steer to an upstairs AP, but the client sees that as -87dBm RSSI instead of -60 to the closest AP which happens to be more loaded. That takes throughput down from 400mbps to 90mbps and the client desperately wants to roam back to the primary AP. On 29.1 this is resulting in every 2-3 minutes trying to steer the client back to the other AP and the client being unhappy 30 seconds later and roaming back to the correct AP.
Just like before 29.x, I would highly highly recommend keeping band steering / client balancing OFF unless you notice issues with your clients. Modern Windows/Android/iOS clients are smart and look at the QBSS load element in the beacons to decide which AP is correct. AP-side steering is fraught with peril because how well the AP can hear the client may not correlate with how the client can hear the AP.
Will this fix our invalid_pmkid with IOS devices :
Fingers crossed !