They are not free but both the FSD Saratoga II TC and the more recent Carenado Saratoga I SP are very close to the real thing. I have about 350 hours now in my PA32-301FG and a 2003 TC.
Both have slight problems in small areas of flight control and of course it all depends on the control setup you have for your sim. For example in the case of the Saratoga the CH-Produkt Yoke I had for the longest time did not feel quite right especially in the elevator axis. I have since replaced that with the Saitek ProFlight Yoke and it is a very good match.
As a member of Manfred's Connie Team my main job was to make sure the girls felt right and the whole team spent a lot of time on getting the numbers to match the real world POH and flight notes we had for the Connie.
The hardest part when doing an airplane like the Connie is that very few active sim pilots have flown the real thing.
But while I could sit down with a few chaps that were lucky enough to fly the real airplane and get as much detail as possible on how it felt in exhange for lunches at airport cafes none of them had ever used Flightsim.
And lugging my entire setup around to have them test our airplane seemed a bit excessive...even if the Saratoga could have easily hauled it...desk and all
Only after the basic FDE was all buttoned up on the L-749 did a former crew member on Connies who is an active sim pilot pop into the CC forums and comment on the comparison real to simulated.
I think the series came away quite well....but of course I am not even going to pretend to be impartial.
Tom Gibson's and Friends CalClassic Convair and Douglas series would be the other group of freeware planes that I think are as close as you can get flying pixels.
I think you need to look at a few separate things in any case.
1. How do the controls feel ??? Which is very much influenced by your setup of course.
2. Does the simulated aircraft meet all the real airplanes numbers.
3. Are you actually willing to spend the time to fly an airplane correctly ???
A great many "problems" that users have with one simulated airplane or the other is that they don't want to commit to step 3. That starts by reading all included documentation and following the correct checklist and settings.
If I had a dollar for every "bug report" that was caused by failure to read the manual my real Saratoga would have her Aspen Avionics Suite already
But then I am guilty of that myself....I wondered if dear JBK had made a small snafu with the latest Ensign when it took seemingly forever for the gear to retract or extend.....I did not read the Readme either before the first flight
Stefan