Each of the two tactics has its advantages and disadvantages:
One advantage is that in some exchanges the commission that the platform charges for a market making transaction is less than what it would charge for a market taking one. Poloniex for example, charges 0.15% for market making, while the fees for market taking is 0.25%.
Another advantage is that we have the ability to buy a coin at a lower price than the one offered. The disadvantage is that it there is no guarantee that we will eventually buy the quantity we want and that the price will not go higher than the price in which this coin is already offered.
In the same manner, when we want to sell, we have the ability to place a sell order at a higher price than the available buying order of the order book, but there is of course the risk that we won’t manage to sell due to a drop in coin’s price or - at best – that we will sell at a lower price than the one we could sell initially.
Market Making is not recommended in case we want to sell very large amounts, because many traders will be willing to sell at very low prices. Another disadvantage is that market making – in general - reveals the quantity we have and the price in which we want to buy or sell and the other traders - trading bots act respectively.
The advantage of this tactic is that our order is executed in a short time - which is very useful especially in cases where we want to apply arbitrage. Another advantage of this tactic is that we buy or sell the desired quantity and not a part of it (except in some cases) and at a price that definitely is profitable for us. The importance of achieving a purchase of the desired quantity increases in case we want to apply arbitrage and the purchase is done at a platform that has set lower minimum trade values.
This tactic is recommended especially when we have large quantities to sell. However, in case that the top rows of the buying orders in the order book are not enough to absorb the amount we want to sell, it would be wise to sell gradually and not at once (dump), since we will eventually sell at a very low price, a fact that will lead to a reduced profitability. An exception in these cases may occur when we have information that the price will fall considerably or when we notice that similar dumps have already been made in the same market of the other platforms.
Finally, another advantage is that we do not give away the amount of coins we have, nor the price at which we want to buy or sell.