Well, it had to happen! One of my two Harmony 900s went into meltdown two days ago. An update failed and after that it was downhill. Even booted into "safe mode" it would not update, and now it won't even boot into safe mode. Also, I noticed my configuration on Logitech's servers was corrupted, some inputs were changed on devices.
I have two because Logitech sent me a second because the first occasionally reset its clock on placing it on the charger. Needless to say, the second did exactly the same! They said I could keep the second.
So, I resurrected the (free!) Harmony Touch, which was collecting dust in a draw, and programmed it. It has improved a lot since I last tried it. My main reservation is still only having favourites on one activity. Does that really save that much memory?
I was pleased to see that you can buy a smart hub and pair it with the Touch, and that combination gives you a Harmony Ultimate plus another touch-screen-less remote control which is restricted to six activities. The 900 IR extenders no doubt fit the Smart Hub too (I haven't tried yet) and also I can now use my phone as a remote. The extra remote also has a CR2032 battery, rather than needing recharging, so that should last a long time.