The pump is quiet and nothing rattles. Extremely well built. The shot to shot consistency is amazing. Stainless steel porta-filter (not chromed brass).
Negative Product Points
The manual could provide a little better verbiage/coverage of programming parameters, but this is a small nit.
Get the optional dry steam wand (un-insulated) installed by the vendor for best dry-steam performance. The insulated wand is a nice feature, but dry steam is better.
Love the auto turn on, but that's starting to be common in high end machines. The all stainless porta-filter means less grunge and less cleaning, as always happens when the chrome wears off the other manufacturers brass porta-filters. The full stainless boilers will last forever.
I wasn't really expecting such a big difference in coffee quality from the S1, but it's there. The machine is just a pleasure to use and has really made it easy to differentiate between different espresso roasts and even bag to bag variances. This machines consistency is particularly important when trying to see the differences in roasting the same beans.
I wish we could plumb in the drain. Definitely go for direct plumb. I can't comment on the water tank, as we're direct plumbed.
Excellent experience from Chris Coffee. This is the second machine we've purchased from them. Their service department is excellent. Machine arrived safely packaged on a mini-pallet, after it was bench tested at the factory.