Liebherr CUN3033 or Miele KD12823S, from different stores?

Hi everyone, I know people are constantly posting asking which fridge freezer to buy but I couldn’t resist posting my own query. Clearly Liebherr is the recommended model on this site. I am looking to spend between 400 and 600 pounds.

I am not looking for anything fancy. My family of three needs to upgrade from a tiny Fridgemaster, kindly lent to us by a friend. I am, as my name suggests, sick of stacking my food and ending up with stuff shoved towards the back getting frozen and often ruined.

I have been looking for ages but it is now crunch time. Here are my top choices:

Liebherr CUN3033 – which is frost free and I can buy it from John Lewis with the free 2 year warranty for 479.
Miele KD12823S – not frost free, from Marks and Spencer for 557. I could go for the KDN12823S which is frost free with some other features but seems to be basically the same machine – it is almost 80 pounds more (which is a consideration, unfortunately). Is frost-free worth it?

I thought I had struck a bargain with the Liebherr until I realized it is a bit smaller than the Miele KD12823S and I have since read of some problems with the automated temperature gauges? And with the freezer compartment. I realize it is always possible to get a dud machine but am happy to avoid automated features if it means having fewer problems. I could also buy Liebherr from Comet which might give me more choice in model numbers but I wonder about their customer service if I did need repairs.

I am happy to go with the non-frost-free Miele if people reckon M&S has good customer service (and if Miele itself does – I’ve heard mixed things about that). I just hesitate to pay the extra money for the frost-free Miele but am happy to get any advice.

Thanks for your help!