I'm fine with Jeff's voice about 75% of the time. The worst he's ever sounded (the only time where I really couldn't listen) was here---
https://www.youtube.com/watch?v=s_xSfwGc5QwJeff's falsetto at the beginning is just so rough on the "I hear the sound" part. The rest of performance went fine--- UNTIL THE AUDIENCE CONTINUED CLAPPING AND IT WAS OFFBEAT AND F*CKED EVERYTHING UP! ... But that has nothing to do with Jeff...
Anyway, I usually don't mind Jeff's voice. I'd take him over Adrian Baker ANY DAY! Here's the worst clip I've ever heard of Baker---
https://www.youtube.com/watch?v=NGt30M7yqlI&list=FLjLWTx2xziJVn8NZOaLBz5Q&index=1Scott was doing the falsetto great, but Adrian was so nasal, it sounded like a Beach Boys parody.
I love Jeff's non-falsetto voice and in an ideal band, he'd be singing mid range parts with Matt on top with Brian's parts.
I am surprise Jeff is still doing the BWPS (And Im' Pickin Up") part with Mikes band. I never had a problem with Foskett vocally when he was in Brians band though his jokes were really tiring. Matt is a better singer by far.