Ever worked as a contract kitchen fitters?

[kf1]

Basically these kitchens are cheap and are what the client is asking and paying for. All the ones you mention do have better options available, but the housing association or whatever specify the cheap ones to save costs.
If you want to fit these type of kitchens go with the company who have the best systems of work in place and have the highest workload. The pay will all be similar, so you want to ensure they are check measured properly and they pay you quickly. H*****s don't manage installations so they would be through a third party. Rixonway and Symphony are both set up to manage and would be better options. Symphony are the biggest and would have the most work available.