There are many differences and similarities between the two routes. The type of goods is just one example. The benefactors of the routes also differed. The Chinese were the primary benefactors of the Silk Road, whereas the Indian Ocean route benefited the Chinese, Indian and the Middle East alike.
However, possibly the most important differences come from the mode of transport.
Transporting goods by sea, for example, was preferable during the Monsoon season. The Monsoons made travel via land difficult, but winds acted to hasten sea travel.
Both routes required 'stop overs'. These stops could provide safety, re-supply of goods, trade opportunities and rest. For ships, these were simply ports - spread along the coastline. For road travel, the stops were 'Caravanserais'. These were placed roughly a day's ride apart - so that caravans could fully utilise their added security at night.
The differences in mode of transport also changed the length of the journey. To travel the entire silk road took approximately a year - but, there were significant trade opportunities along the way. The sea voyage was only ~six months long. Boats could also be loaded with a larger volume of goods, compared to the camels and caravans of the silk road.
Image Credit: University of Chicago (see link under)