Have not flown the Cessna 200's but did most of my flying in the fixed C-172 before flying the C-172RG.
Found that the usefull load was alot better (you actually could fit in 4 POB, fuel and bags), and it flew a good cruise speed (all things considered).
I only did about 60 hours in the RG and the particular RG I flew was starting to get pretty tired but none the less was a welcomed upgrade from the trainer 172's - with the addition for me being my first CSU a/c.
Dont know how the cabin size compares to the 182 but would assume its about the same. Flap speeds are pretty good too - 130kts/100kts. Fuel I used to plan for 40ltr/hr (35ltr/hr fixed 172) and never experienced any major tech. probs.
If your buying the a/c Id prob go for the 182 as sounds like it preforms much the same but with the fixed gear I guess is one less thing to go wrong ($$$$), also theres a lot more of them (spares etc), but if its just for hire go for it! - a fun 4 seat single piston x-country machine.