We had a Mereway fitted bathroom in our last house. It was very good quality and beautiful and well made and we will get another one in this house when I get round to sorting out the bathroom. No experience of Hacker but I guess you are looking at the difference between a mid-range well-made English kitchen and a mid-range well-made German kitchen. THere are a few threads out there about the differences:
That thread might give you some idea of the questions to ask/specs to compare.
German kitchen makers tend to make everything to measure, so you may find you get cupboards that exactly fit the space exactly without the need for filler panels or wasted space. My mum got one because she is 4'10'' so she could get a lower height one made easily.