Overdrive!?!?!

[DeepPurple]

200-4R vs. 700-R4

Essentially there isn't much difference between the two of them. They'll handle similar amounts of power (with proper buildup) and have their advantages and disadvantages.

Chiefly in favour of the 200-R4 is the better set up 1-2 gear (which can mean quite a bit in a stop-light duel) and the fact that the rear seal is much better than it is in the 700-R4 (if you ever have the chance, check how loose the yoke is in a 700 in comparison to a 200, it's rather odd...) Some have a cable driven speedo (of course some 700-R4's do also) although later models did have electric stuff attached to them.

Weighing heavily against them is the weaker stock form (unless you can find one out of a Buick Grand National/Regal T-Type) and more so than that is the cost to upgrade. Most local speed places will know how to build up the 700, but won't know how to do so with the 200-4R. Additionally it just flat costs more. More internal stuff will need to be done (the clutch packs blow, period. And the bands are pretty bad. The sprag gear is fair enough but it's one of the easier upgrades) to it to take the same amount of horsepower that the 700 would need with less work.
Also there was more call for hop-up parts for it as it came in camaros and trucks, vs. full size "luxury sport" cars.

The 700-R4's merits and demerits have been argued here ad nauseum. Needless to say unless it's after 86-87 it's weak (of course this means you have to get the electronic stuff) and the 1-2 jump is so stupid you have to wonder if that engineer is still gainfully employed.

The 200-4R isn't weak, but it takes money to fullfill it's promise.

Me? I say for for the 4L80E or better yet figure out a way to convert that new Allison behind the Duramax Diesel to your truck (5 friggin gears in an auto!)
Course it's not my money...