So far I've only read of one issue with the steam on the 7000 (apart from the thermo issue) and it sounds like the one the EM6910 had - steam weakens and then stops.
In my instance, and that of a few others who read what I tried, it came down to the Sunbeam advice in the manual to never put cleaner through the steam system. It seemed strange to me because the description for both water and steam systems is the same, stainless-lined thermoblocks and the tubes are the same inside.
I was getting reasonable steam when I got my 6910 but after a while it was taking longer to start steaming. So I ran Cino Cleano (recommended by local roaster) through the steam path and it improved a bit. Then about the 3rd time I did it, I inadvertently left it running for maybe 15 minutes. I came back inside to a coughing and spluttering steam wand then it suddenly got REALLY loud and strong. When I emptied the container I had under it, there was some dirty brown muck in the water.
Since that time the steam has been great (for a 6910 - the 7000 is even betterer
) and running cleaner through the wand has become part of the ritual.
I may be preaching to the choir on this next bit...
I think it blocks up because of another recommendation from SB in their manual - leaving the wand in the milk until the steam stops. In a physics sense, steam is expanded water and the pump puts it under pressure, so when it stops the liquid outside the tip has a partial vacuum to fill and milk goes up the tip. Over time this clogs the system I think.
In the barista course I did I was taught to remove the wand from the milk before the end of the steaming; with a little practice it becomes easy to know when to do it and if you take the jug away at the angle of the wand there is little chance of splash or bubble.
And there's a side issue of crap they put in the water that might get sent through the steam pipes. There is no reason I can think of why the steam system would NOT have similar issues to the water system so regular cleaning should be recommended.
If there is something else that happens with the steam, please let me know; I prefer to have possible failure parts on hand for fixes; saves stress to the missus when I don't get my coffee.