Nowadays we basically only shop at Höffner and Segmüller - for one simple reason: Segmüller offers the lowest price guarantee (5% below competitor price) also on online offers. So you just go with an online offer and point out the lowest price guarantee. We have bought chairs, dining tables, living room furniture, and sofas of decent quality (including Hartmann or Niehoff) comparatively cheaply this way. With the dining table, the salesperson even pointed out that there was an even cheaper price on the internet than the one we had.
We shop at Höffner because I get a discount there through Corporate Benefits and here too the best price is honored. This way, good prices add up and we paid significantly less for a solid wood lowboard and a display cabinet than on the internet (a €400 difference to the cheapest internet price). At Höffner, that pseudo-40%-only-today discount place, I especially enjoyed seeing the salesperson sweating over the price for once.
The cheap prices for the lowest price guarantees are often found at Porta (especially with their regular discount promotions), Ostmann, or Zurbrügge.