I have used Mercury since the name was born in Zambia. For sure, when you are talking of things like phones, rings wrist watches, viagra, toys, shirts and lastly sweets; they are the best to go. It takes about 2 weeks. But if you talk of "tangible" things, i mean machines....look elsewhere and FedEX are a good option because one works on time. Mercury's price is a give away and you would laugh all the way home or to your office. Mercury is just a bunch of few loafers employed by some virtual person who has this nice skill of ensuring that goods whether small or big will find there way home where they belong but without much respect on time.
My only bad experience with Mercury is that the girls they employee are too on top of themselves and wouldn't rely consider their customer as such may be because education is very important in the execution of any jobs.
I have always given respect to white people. If you walk in their premises, there is this warmth, they would offer you what you really would need in a hurry like water or coffee and just that welcome note that goes with them. Mercury is typical of our black culture in terms of business interaction with customers. In fact they are near to bank employees. Much as they see and count, bank and cash billions of other people's money, most of them think bigs way out of their duties.
Therefore, if you want to get small things, use mercury, but for bigger things, FeDEX are way better and DHL are just bunch of shit. I mean in Zambia.