Figure I was preaching to the choir Dan!
Yep..have a few old 1.25" Whiteside Mortising bits like that
Still using them occasionally on roughing wet wood and bark cuts that may have some embedded mud while they were firewood....
Then when I get within .2" of where I figure I'll stop....swap over to a fresh/clean Whiteside for last little bit.
Wet wood quickly builds up junk on the cutter, and taking a minute to brass brush it with Bladecote makes a huge difference!
Even bits that Look clean...swiped with a fresh Viva paper towel have a thin coat usually after a few passes that increase sanding
Have a few people that regularly do slabs/tabletops and Love that bit for the reduction in sanding...although somewhere in the back of my mind, I remember in some circumstances they removed two of the cutters(?).
If all my stuff wasn't so small...I'd probably invest also:)