In terms of how practical and economic value, from experience.

Looking on autotrader the prices are similar (relative of milage) and MPG, 0-62mph times, top speed, etc are all very close, yet the ST200 has 35 more bhp?

 

The 200 is the one to go for, but a lot of 24/200 are old and ropey these days, finding a good one isn't easy

 

If you go for a ST200 look for rot underneath seals floor pan etc, ive found a lot of real bad ones that on the face of it look really nice on top, also make sure there are no ticking noices from the engine, also a comon problem. Be carefull when buying.