Portal's best feature is the number of blockchains it integrates. Portal allows you to bridge between over two dozen blockchains, and more are being added constantly, so if you are trying to bridge from a less prevalent chain to Solana, Portal might be the way to go.
Portal is built on the wormhole, a cross-chaining bridging protocol that uses the burn-and-mint bridging method. This process involves locking the original asset on the source blockchain and minting an equivalent wrapped asset on the target blockchain. Once the bridge is completed, you can swap the wrapped asset for a different token.
Wormhole recently integrated with Circle and now allows you to swap USDC stablecoin across different blockchains without incurring platform fees. However, you'll still need to pay gas fees.
NOTE: If you use Portal and the transaction fails to complete, you can finish the bridge by clicking "Resume Transaction" and inputting the "source chain transaction hash." For a more detailed tutorial about how to resume your transaction, please check out this post.