Pretty simple. I had one Dodge 3/4 ton bought new by me in 2002. 3 trannys by 68,000 miles. Factory, rebuild by Dodge, then a Jasper and traded. Maybe the Jasper would have lasted but I work for a living and was not going to sit back and wait for the results. This truck replace a 2001 F-150 that pulled the same load as the Dodge without complaints. Would I buy another Dodge? Yes, especially from the local dealer. They took great care of me but I will only do so when I think the product is better than the options and right now I do not see it.
I have had about a dozen Ford trucks since 1997 and not a single issue. 3 of them Diesels that pull big loads every week, nothing less than 12,000# for them to roll. Any lighter I take the 1/2 ton Titan.
I have owned 4 GM's and never had a tranny problem but have had plenty of other issues. Closest thing to a tranny failure in them is a Transfer Case that turned into a grenade. As for the Allison my neighbor is having issues with his right now. Second time in his 2007 Dmax with 70,xxx miles so no, its not bullet proof by any means. And no, its bone stock and has been since new. Heavies pull for him is 11,000#.
These sites are just opinion. You have yours and I have mine. Like I said I work for a living so I buy what works for me. You buy what works for you.
Chris