I've had my S1V2 for about 1 month now and am very happy with my decision.
I don't have the drain option since the machine is near a sink and the tray is easy to remove and dump. What little I've read about the stock option is that it's not that great and people have had better luck with a DIY solution.
It may only take both boilers 10-15 minutes to hit their temperature (in 20-amp mode) but I'd say the 40 minutes is about right to make sure the entire brew path is heated. I've been leaving my brew boiler on 24x7 and turning the steam boiler off when it's not needed. It only takes 5-10 minutes to come up to temp for steam or hot water. Not the optimal solution but it's the best one for me to have the machine ready in the morning and for those spur-of-the-moment coffee desires.
I also have found, as have others, that draping a towel over the cup warmer keeps the steam boiler from cycling so often. It also keeps the cups very warm without heating the underside of the cabinets.
I do notice that, if the steam boiler is off, the brew boiler takes a little longer to rebound from warming and blank shots. I'd need to check the diagrams but the brew water may pre-heated by the steam boiler before hitting the brew boiler, resulting in a quicker rebound.
If you'll be making milk drinks, the VII has loads of steam power. Some people have replaced the standard steam arm with a longer version and/or the standard wand tip with one with smaller holes. The latter will slow down the steaming speed. I drink mostly straight espresso or Americanos so haven't gotten either yet. Both parts are available from Chris' Coffee Service and they may in fact install them for you if you buy them and the machine from them (call to confirm).
Lastly, not to detract from Dan's and the HB folks' great work here, check out the
The International LaSpaziale S1 Vivaldi Cafe site for more information than you wanted on the Vivaldi line.