The New York Central ran comparison tests of GE U30B, Alco C430, and some off-brand thing called a GP40, using (i.i.r.c.) hoppers full of ballast as test trains, on some hilly branch line in I think upstate New York. Tests and outcome are described in a C430 article (by Steve McMillan, if I haven't confused names in memory) in "Diesel Era" magazine, description repeated in the "Alco 4 Axle Century Models" (or some such title) book put out by the publishers of "Diesel Era." (Sorry not to have more precise bibliographical data: I've just moved house, can probably find things in a few days if nobody else writes in with the details....)
From memory: In an initial trial, the C430 didn't seem particularly distinguished, and Alco spent a couple (?) of months fine-tuning the wheelslip control system. When the tests were repeated afte this, the U30B managed to climb the hill with the heaviest load, but the Alco was significantly faster with a slightly lighter train, suggesting perhaps that just above stalling speed it was a bit more successful at turning horsepower into tractive effort. (The GP40 also did quite well on these tests: its shoddy, off-brand, traction motors apparently didn't affect its short-term ability to lug too badly, though on a longer hill its motors might have fried faster than the 752s on the U30B and C430. Grin!)
... In principle, the Alco-designed "Hi-Ad" trucks used under the C430 ***COULD*** have been used on GE locomotives (after all, they were designed to fit the same center plate on an Alco locomotive's underbody as the Commonwealth truck used on most 4-axle GE U-series). I don't know who owned the patents for the truck design, but I would think (hey, a little money is better than none at all!) they would have been willing to license it to GE after Alco went out of business: neither GE nor any of the railroads buying U18/23/30/33/36B locomotives seem to have thought the Hi-Ad was ENOUGH better to make this worth while. (That's a HINT to model railroaders with a taste for "alternative history" prototypes!)