I've also been using the Apple Virtualization option with Linux VMs in UTM and have had zero issues whatsoever. The biggest benefit to doing so in my opinion isn't necessarily the noticeably better performance, but the RAM usage. I've noticed that Linux VMs in UTM that run using the Apple Virtualization Framework use significantly less RAM compared to otherwise because the framework provides dynamic memory allocation. This makes it very well suited to running Linux VMs on systems that have less memory (e.g., an M1 MacBook with only 8GB of RAM).
The only thing I'd like to see added to the framework is the ability for nested virtualization (which is now available in the M2 chips, but isn't built into M1 chips).