THORChain is a Decentralized Liquidity Network. It facilitates cross-chain liquidity pools with no pegged or wrapped tokens.
Uniswap is a decentralized protocol for automated liquidity provision on Ethereum. The keywords here are on Ethereum. UniSwap does not facilitate cross-chain swaps. If you want to swap between an ETH or an ERC20 token and a token on another chain... you can't. This is why UniSwap, and every other UniSwap clone and on-chain DEX need "wrapped" (a.k.a. "pegged") tokens, like wBTC, to represent an asset from one chain to another.
Wrapped tokens are not native tokens, and in many cases, require trusting a centralized authority. Wrapped tokens are also tedious -- they require manual effort to wrap/unwrap, and more effort to exchange for the true underlying asset.
Ren is a way of wrapping Bitcoin and representing it as a Ethereum-based ERC-20 token so that those tokens can be used in Ethereum-only liquidity pools. Ren just performs the wrapping/unwrapping behind the scenes, so it's transparent to the end user.
THORChain is a liquidity pool that works across chains so there is no need to wrap BTC in ETH.
With Ren, you have to trust that the Ren protocol will always exist to turn your wrapped BTC back into real BTC on the Bitcoin blockchain.
With THORchain, your BTC is always BTC, and your ETH is always ETH without any wrapping.
Binance is a CEX (centralized exchange). Centralized exchanges can allow users to trade assets between chains because in reality, your exchange wallet is essentially a few rows in a database. Not your wallet, not your tokens.
THORChain's secret sauce is Bifröst, a cross-chain bridge protocol.
Bifröst is the glue that holds the entire THORChain ecosystem together, enabling the seamless trading of any digital asset across any distributed ledger.
Atomic Swaps are mostly a failed effort to accomplish cross-chain swaps. This solution requires both blockchains implement the Lightning Network, and currently only a small number of chains support this. Additionally, there needs to be an active open connection to link buyer and seller when using Atomic Swaps. You cannot currently swap between ETH and BTC using atomic without significant effort. This solution is a non-starter.
THORChain offers the following breakthroughs:
Complete transparency on the liquidity and logic of the entire network at all times.
Distribution of risk across the 99 THORNodes.
Permissionless access to global liquidity.
Manipulation-resistant price feeds.
Deterministic always-on liquidity for all assets.
Shared incentives for all participants.
Non-custodial staking of assets.
On-chain swaps with no pegged tokens.