Which home providers for OWL?

I'm bumping the thread. We had talks with Splietker Bau from Rheda and Kelle Konzept Bau from schloss-Holte. Both were very good conversations. Since we don't have anything confirmed yet, I wanted to ask if there are any "insider tips"? ;-)

Which Splietker? The blue or the red one?

I know the blue Splietker and our neighbors are building with Kelle. With Splietker we only had talks and then drifted apart on the topic of costs. At the time, it was too expensive for the offered floor plan with the limitations in construction standards.

The consensus here in the forum was: too design-obsessed - should pay more attention to everyday routines.

We have now largely caught up with our general contractor regarding the superficial cost disadvantage with Splietker. Compared to the contract signing, we are now >20k€ in the plus. However, this is mostly planned by us or we were able to realize some items from subsequent add-ons even cheaper than feared.

What Splietker had offered us back then, we have now almost reached - but we still get more house, for example

[*]Higher basement rooms
[*]Basement insulated on the outside (Splietker simply didn’t want to because he thinks the insulation will get damaged?)
[*]Basement heated + ventilated via controlled residential ventilation
[*]Bafa-eligible heating/ventilation

Splietker is very focused on geothermal energy, as I perceived at the time, and doesn’t like the air-water heat pump. That wouldn’t work for us because of the water authority. Floor heating design was not an issue with Splietker back then, so I don’t know how they would have handled room-by-room heat load calculation and wall heating in the bathroom.

Kelle also seems to be great.

The red Splietker is with us. I don't know the blue one. Kelle would like to build a basement with underfloor heating, but we simply don't need one. We need to discuss that again.

Then I retract all my statements. I have not spoken with the Red one and do not know anyone who built with them.

I would have told the Blue one blindfolded, go ahead. As long as the floor plan really offers what you need, there is hardly any risk.

Which Splietker? The blue one or the red one?

Are these competitors from two lines of a family (or just namesakes), who differ only in the logo color? - what differences in name suffixes does the non-insider notice?

A long-established family business that has split up for "some" reasons. Blue is the continuation of the original, red the spin-off.