The two markets are different products, and the comparison is not a ranking. It is a question of which trade-off you want. This is the comparison, stated without the spin, and the decision it leads to.
The catalog
Torzon is larger. It has more listings, more vendors, and a wider range of categories, which is the direct result of a lower barrier to entry for vendors. Nexus is smaller, and the size is the cost of the vetting. Vendors clear a review before they can sell, and the catalog is the set of listings that passed. The difference in size is the difference in how much checking has happened before you see a listing.
The escrow
Both use market-held escrow for the standard flow, so the money path is the same shape on both. The difference is in the dispute handling, where Nexus is faster, with resolutions measured in hours in the straightforward cases, against a queue that is longer on the larger market. The speed is the trade for the smaller size. Fewer cases, handled quicker.
The coins
Nexus takes three coins, Bitcoin, Monero, and Litecoin, and recommends Monero. Torzon takes two, Bitcoin and Monero. The extra coin on Nexus is a convenience for people who hold Litecoin and do not want to swap. It is not a privacy difference, because Litecoin is as public as Bitcoin.
The interface
Both are conventional market interfaces, and neither is the novelty. The difference is in the details, the search, the filters, the speed of the page, and the way the reviews are presented. The details are the part that shows up in a daily session, and they are the part that is easiest to judge by trying both, which is what the comparison is for.
Who each is for
Torzon is for the buyer who wants the largest catalog and is willing to do the vendor checking. Nexus is for the buyer who wants a vetted catalog and fast disputes, and is willing to accept a smaller selection. Neither is wrong, and the choice is the trade-off, not a verdict. If the catalog is the priority, Torzon. If the dispute speed and the vetting are the priority, Nexus.
The Nexus overview covers what Nexus is, and the fees guide covers the cost side.