I just purchase my 2001 36 MkII two days ago! I am about to make the seven day trip from NC to VA so I won't comment on the sailing traits. (I have sailed on many Catalina's before and have found them to be quite delightful.)
I looked at Hunters and Beneteaus as well as two Catalinas. What sold me was that only the Catalina had a solid fiberglass hull instead of a cored hull. It isn't that a cored hull is necessarily bad but the older the boat, the more likely that somewhere along the line, some incident may have compromised the outer hull. That could lead to rotting of the core. That can only be found through the survey out of the water. (I also liked the four winches on the Catalina instead of just two.)
My biggest concern was the engine. I recommend that as part of the survey, have the oil and transmission fluid sent to a lab for analysis. That will tell a lot! Check all the hoses. (I had many of mine relaced.) I also replaced all the filters and impeller. I wanted peace of mind from the start! Before the survey, you can do a poor man's test. Pull the dip stick. It's OK that the oil is bitch black. The oil should still feel thick and viscous, meaning that it hasn't broken down. It should smell like oil, not foul or like fuel. It should not be gritty.
Check the stuffing box. The occassional drip is expected. Check the keel bolts. No corrosion. When it is out of the water, check for the "Catalina Smile". That could be red flag if significant. (Mine did not have the smile!) They will also check for blisters. Some minor ones are OK. (Again, mine had none.) Check that the Cutlass bearing is in good shape. (No wobble)
Check for signs of hatch/port leaking. Check that the windlass works. Steering should be firm, no backlash. Check the chainplates for corrosion. Make sure the head is completely functional and does not leak. (I replaced my head.) Make sure the fresh water system and heater work. Check that the stove and oven and the LPG solenoid work.
Go through all of the functions on the boat that are controlled by the breaker panel. When I bought my boat, I knew that it needed some attention and that was baked into the price but the boat had to be Functional (everything worked as stated by the owner), Safe (sound hull, standing and running rigging, life lines, etc.) and Navigable (all in compliance with Coast Guard regs).
Oh. Most important! Does the stereo work!
Do as much of this on your own as you can. A survey will do it all again but if you find these issues before hand, you can walk away before you have the expense of the survey.
Good luck!