We've shopped around a long time for a good fulfilment system which doesn't break the bank. Occasionaly you'll find a good one, but the cost is more expensive per month than getting another member of staff, or the features just are not there.
Then we found OrderHub... it's beautiful to look at, simple to use and has all the features you need and nothing you don't don't need.
I trained my staff in about 10 mins, that's how easier it is to use.
The team behind it are also very helpful and have worked with us to make the system even better with full support for couriers.
I'd rank it a high 9/10 (If it gets Magento support it will be 10/10!)