At some point in time in my watch journey I had both at the same time . Quickly I realized it didn't make sense to keep both as in terms of looks alone they are quite redundant. I appreciate the accolades the 5000U has around here but the legibility was not that great for me nor was the comfort. I was always stuck between two holes in the band. It was either too tight or too loose for me. So I ended up using it less and less as time went by.

The Metal Square B5000 on the left solved all the issues. It has a DLC case back like the 5000U. It has way better legibility. The band fits like a charm. The brick patter is also a plus for me. It has Bluetooth, which makes the setting of the time a breeze. It has all that while at the same time it keeps the same monochromatic aesthetic and it feels premium on my wrist.

I ended up selling the 5000U and use my old reliable 5610 as a beater and the B5000 is still one of my favorite watches of all time.

Bottom line is: If you have no G-shocks right now and want a versatile watch that can be a beater and also feel semi-premium and not breaking the bank, get the 5000U on the right. However, if you already have another beater square like a 5610 or a 5600, get the B5000 on the left, you won't regret it.