Takayama Fumihiko has released a new version of UNesterDC, which you can get from his site.
Here’s what’s new in the latest version:

• rewrite sound code.
  
• improve auto frameskip
  
• adjust menu cursor speed
  
• add ‘remove vmu files menu’ (press B at main menu)
  
• update KOS to 1.1.4.
  
• fix mapper 5 crash bug.
  
• 3.0t5-pre5 can’t read 3.0t5-pre6 save data (pre6 can read pre5 save data)

He also had this to say:

“Now, I feel fullscreen is playable speed at auto frameskip. But the implement still buggy, be careful fullscreen play.”