I had the same question a few months back when I was putting in my new 235. I opted to stay with the bronze bushing. I was using my original 1940 transmission and there was a small amount of wear on the end of the input shaft that goes into the bushing. I was concerned that uneven contact on the needle bearing rollers could cause them to bind and gall the shaft. Also, my experience with antique motorcycles has show than shafts that are designed to run in bushings originally are not hardened that same as shafts that are designed to run on needle bearings. Needle bearings require are harder surface to run on because the the shaft acts as an inner race. Those needles are a lot harder than the bronze bushing.
I figured the old bushing lasted 65 years, so a new one ought to last at least that long considering the amount of driving I do with it.
Steve
