After something well over 1000 instructional hours on IIIs and IVs perhaps I may be permitted to offer the following advice.
1. It has no real vices although the control loads, especially rudder, can be a bit heavy. However, that is what the trimmers are for. It is, however, a pretty stable platform and if properly trimmed will do all the flying for you.
2. I have rarely had any asymmetric climb problems, although to be honest it is rare to operate at max all up weight.
3. On finals it is sensitive to small speed and power changes so for that stabilised approach keep it in trim. Not a problem as all the ones I have flown have an electric trim.
4. While on the subject of finals, it is not forgiving if you try a high, steep approach. If you do find yourself higher on the glidepath than the ideal, reduce power, lower the nose and get back down to where you should be. In a light single it is possible to close the throttle and glide in to land from a steep approach. Try that in a Seneca and the only thing that will beat your rate of descent is likely to be a free fall parachutist. The reason is that when the throttles are closed the props go to full fine in an attempt to maintain max RPM. Since there is not enough power from the engines what happens is that the airflow now drives the props giving rise to huge amounts of drag.
5. Someone made a comment about flat landings. It is easy to do but nearly as easy to prevent. At the same time as the throttles are closed for the landing and the flare is started, trim nose up [electric trim remember], and keep doing so until the mainwheels touch.
6. Engine failure after take off is not a big deal but don’t expect much in the way of a rate of climb unless the speed is reasonably close to blue line [92 knots]. Also at full power and blue line the rudder trim will not take out all the foot loads.
7. Stalling is conventional but expect fairly high stick forces at the stall. It is not advisable to trim all the way to the stall, about 85 knots is a good time to stop. The reason for this is not aerodynamic but more a matter of the stick forces on the subsequent recovery. As the turbos cut in there is a pronounced pitch up tendency. If the aircraft has a lot of nose up trim at this stage events, shall we say, can get interesting.
I don’t know what variant you will be flying, but there are two and three bladed prop versions around. There is no appreciable difference in any of the handling qualities. The three bladed ones need a slightly higher power setting on downwind and ion the hold, but that is pretty well all the difference you will notice if you fly both variants.
The bottom line is that I find it a pleasant aircraft to fly but one that needs a little bit of attention to detail to fly consistently accurately. Enjoy and good luck with the IR.