Not sure if they're classed as a competitor as they sell only used tech (so delete if they are) but just a quick guide about my experience.
I bought an S23 Ultra from there in "excellent" condition. Excellent is described as:
Screen: Perfect condition
Body: May have barely visible micro-scratches, not noticeable from 20 cm away
I paid £5 for express delivery as it was yesterday and I wanted it today. Their customer service was pretty helpful in confirming it would be sent via DPD express for a Saturday delivery, and the purchase process was very easy and straight forward.
However, it turned up this morning and this is supposedly their definition of excellent condition:
Ironically the body of the phone is perfect.
You have to pay an additional £6.99 on top of the price for their quality control checks. No idea what sort of quality control this went through but it wasn't thorough. I assume that it's difficult for a company like Back Market to be completely in control of their 3rd parties who sell through them (this came from 4gadgets), but this is still not great.
The cost for the S23 Ultra 512GB in excellent condition was £641. I was quite pleased with this price as my intention was to send back my S24U that I'd also bought at the same time if I liked the S23U as it was almost double the price, but that plan has been blown out the water so I'm lumped with the S24 now!
Hope this helps anyone considering Back Market.
I bought an S23 Ultra from there in "excellent" condition. Excellent is described as:
Screen: Perfect condition
Body: May have barely visible micro-scratches, not noticeable from 20 cm away
I paid £5 for express delivery as it was yesterday and I wanted it today. Their customer service was pretty helpful in confirming it would be sent via DPD express for a Saturday delivery, and the purchase process was very easy and straight forward.
However, it turned up this morning and this is supposedly their definition of excellent condition:

Ironically the body of the phone is perfect.
You have to pay an additional £6.99 on top of the price for their quality control checks. No idea what sort of quality control this went through but it wasn't thorough. I assume that it's difficult for a company like Back Market to be completely in control of their 3rd parties who sell through them (this came from 4gadgets), but this is still not great.
The cost for the S23 Ultra 512GB in excellent condition was £641. I was quite pleased with this price as my intention was to send back my S24U that I'd also bought at the same time if I liked the S23U as it was almost double the price, but that plan has been blown out the water so I'm lumped with the S24 now!
Hope this helps anyone considering Back Market.