Sparrow has a lot of flexibility with support for multisig and many different script types. However, Sparrow will leak all of the addresses in your wallet to third party servers during syncing unless you've already connected your full node first.

Wasabi specializes in privacy and does all network communications through Tor by default. Balance discovery uses compact block filters (BIP157/BIP158) by default to synchronize privately in a lightweight way. This reduces the data requirement compared to a full node by ~99% without leaking your wallet's addresses to anyone else's server.

The main feature of Wasabi is the ability to participate in coinjoin transactions. Coinjoins bundle your inputs with other users into the same transaction to fool tracking attempts made by blockchain analysis. Sparrow removed their coinjoin feature in April (although advanced users can build coinjoin transactions "manually" using Sparrow's tools).