I'd also ask this question over on the Appliances Forum. Lots of great help over there.

I love my combi steam oven, and am constantly surprised at how much use it gets. I use it daily, I think in
part because it of its size. I too would have some concerns about
the size of the Thermador, but having said that, I was very surprised at
how much room my combi has. It didn't look nearly that big in the
store!! Have you ruled out the Miele? I would choose it over either
the Wolf or the Thermador for a few reasons. Miele can be plumbed in,
and this is a really great feature imo. Also, I don't think either the
Wolf or the Thermador have a broiler, if that matters to you. IIRC, Miele and Gaggenau have been making steam ovens the longest.

Wolf. Thermador is too small and the water reservoir is inside the oven, losing steam if u need to refill

Miele. They have both a plumbed and a manual fill model. The tank of the manual fill model is on the outside of the unit and does not interfere with operation. The Miele Steam oven also has a broiler. I believe the other steam ovens don't have broilers except for the Gaggenau. Take a look on the appliance forum, there are a lot of threads about steam ovens

Good luck!

Whatever you choose..make sure you have someone locally that can service the oven. I will only choose something that can be serviced without hassle.

I had the Gaggenau for 12 yrs and adored it but local service is not available. Neither is Miele. So it's between Thermador or Wolf for me.

i will watch your thread.

We love our Wolf CSO and probably use it daily. I have 4 ovens counting the micro but if it fits it's most likely going in the CSO. Ours is 4 yo and has had to be serviced once. The water heater needed replaced. I have no local service anymore but did when I 1st purchased it. I had one call in the 1st year but oddly a brand new circuit failed in our service panel which stumped the service tech, wasn't the ovens fault at all. Fortunately the oven isn't that heavy and fits easily into the back hatch of my car so I just took it out and took it to the service center 70 miles away. I live very rural so everything is far away. I had it back in a week and cost me $160 out of warranty to replace the heater. Back to working like a charm. It was a pain but worth it.

On a side note, we were using our filtered well water for the 1st 3 1/2 years but have since switched to bottled water (not distilled) as our well water, though filtered still has a lot of minerals which will deposit out over time. The guy who replaced the heater mentioned that it needed the deposits cleaned out even though we descale fairly regularly. So we switched to see if that will help (most assuredly it will).

The size of the Wolf was a major + for me, we also have a Wolf convection oven so it helps that the stack is all one mfg.