I didn't get a lot of details for my review; but it's pretty transparent. The machine warms up in about 20 minutes whether the steam is on or off, and I don't notice any glitches or slow downs when I steam for tradtional cappas and make shots at the same time. But there's 2400 watts total in the 110/120 version, so while both can run together for a few minutes, they can't run together all the time. In any case, however they time share; I haven't noticed any problem with it.
People who've used it to make a bunch of bigger milk drinks in a row may have a better handle on any limitations.