I am very positive by the supply, logistics and service aspects here in Mindelo from what I heard and experienced myself.
In the two market halls I visited today, there was no tourist mark-up and I also got my broken iPhone glas repaired at competitive rates in less than two hours time!
The rip-off takes place somewhere else, when you buy local papaya at 1.5 Euro per kg and fresh tuna filet for 7 Euro per kilo. Not sure where fair trade comes in.
Also the service in the marina is excellent. Laundry is being picked-up in the morning hours from the boats and same day evening hours returned back. I also received good feedback on services done by the boatyard for some fellow sailors.