I guess intended usage is what would make my consideration of either of the 2 transmissions. If the car will be abused or raced and have a high horsepower engine in it I'd opt for the 4L80E, if it's gonna be just road driven with a stock engine then the weaker 200 will probably serve you as long as it has some of the better parts in it. Remember this transmission was originally designed to drive a stock car and engine with no abuse. The biggest engine it was behind was a 305 chevy to my knowledge.
The 4L80E was designed from the venerable T400 and GM added an OD because the 700 or the 200 wasn't tough enough to put in a 1 ton truck with a B/B or a turbo diesel in front of it. GM needed an OD transmission that would haul the weight of the 3500 HD truck chassis with payload and even GM knew trying to haul anything with either one of those transmissions would be financial suicide when it came to warranty claims.
The 3500 HD truck can haul itself along with just over 6000# according to chevy, you know damn well that the owners are going to try to haul 10,000 + with it if it's rated at 6000#. That gives the 4L80E a huge safety factor over the 200/700 transmissions.
Is it more expensive to switch to initially? most definitely it is, thing is a transmission is not considered a wear item by most people that periodically needs replaced like brake linings.
200 needs to be built with tougher innards to put behind a high torque engine that it was never originally designed to be behind. Of course either will need a different torque converter. The 200 can hook up to your standard speedometer cable. The TV cable adjustment is critical so you don't toast your new transmission in a few miles of driving. no adapter plate because most 200s have the BOP bolt pattern along with the chevy, dual fit.
4L80E is of course electronically controlled and needs an TCM to operate along with it uses an electronic speedometer so there is no cable hookup. 4 ways to have a functional speedometer
1)retro fit kit that gives the 4L80E a place to hook up the standard speedometer cable, kit retails for around $500.
2) an electronic motor driven add on that can convert the electronic signal to drive a standard cable speedometer, about $300
3) use a later model electronic speedometer head in place of your original cable driven one, would require some work to find a used late speedometer that would look right in an older car, whatever you can buy one for from a wrecking yard.
4) there are now GPS speedometers available that can be bought and of course need no hookups to the car to read your speed, ones I've looked at were approx $250. Of course it's not going to work in a show car needing all original instruments.
Since the 4L80E only came behind the chevy family of engines the bolt pattern is not going to bolt up to a Pontiac, necessitating an block to transmission adapter plate, fairly cheap to buy, usually less than $75.
TCM and wiring harness, the one Jake recommends is about $600 discounted $100 if you have him build your transmission. The TCM is also very adjustable to tailor the transmission manners to your combo, the 200 not so much.
The 4L80E is going to run close to $4000 if you purchase everything at Jake's and have him build your transmission. The 200 is close to $2500.
Transmission tunnel may need a few dents in it with the 4L80E, although I have heard the ribbing on the transmission case that is the offending problem and can be ground down easily necessitating no hammer mods at all.
The cost of only doing the job once and never having to be concerned if the transmission will break the next time you hammer the throttle on your car,
PRICELESS!!!!!!!!
If you consider engine mods later on the 4L80E gives you room to grow without worries, the 200 not so much.