for that year i would stick with the Chev as from 97 to 99 the ford's trannie's were noted for being crap in their trucks, i myself picked up a 2000 expedition because a friend has one with 327,000km on it and it still has all original mechanical, i tow a.t.v's with mine and here in b.c. Canada some of these hills will test any truck so far i have had no trouble and i drive it hard sometimes, all i do is change all fluids on a regular basis, IE....oil every 5000km , trans-fluid every 25 000km or sooner if i have done a lot of a.t.v.ing.
i also had a 91 suburban before and the tranny went at 243,000km only after i got water in it from crossing a river on the mountain trails so i think the Chev for that year will do good by you, good luck.