They don't call the Aztec the "Aztruck" for nothing! From my understanding will haul everything including ice, easy to fly. Only have a little time in them including a bit of ice. Considering that the original design was based on the rather underwhelming Apache it's quite an improvement.
The 310 is a great aircraft as well but is very different. I got my MEL in the 310 and my instructors would say that if you can land a 310 you can land anything.
The 310 speaks big airplane, it sits high on the gear and seems very substantial. It flys and behaves like a bigger plane. If you are stepping up from a 172 or similar aircraft you will have fun as you enter the pattern downwind at about 120 Kts, that's faster than what the 172 cruises at! Some do not like the way the 310 flys as it has a pronounced dutch roll that many people complain about. I would say that the Baron has a bit more harmonious control response, but you are constantly rubbing elbows with whomever you sitting next to or banging you head on the upper side wall. The 310 has a much nicer cabin. I have flown both the short snout and long snouted models. Personally I never saw what the big deal was in landing any of the 310's.
The earlier model 310's I believe were 240 HP pressure carb O-470's. Later models have a fuel injected IO-470 260 HP engine. The R models have IO-520 285 HP engines. They will drink more fuel and have some cracking problems from what I have heard. My favorite model is the 310Q, the last model with the IO-470's.
The Aztec and 310 are a few of the light twins that were from the beginning designed as such. Many others light twins are basically single aircraft that have be "twinned" like the Travelair, Baron, Seminole, Seneca, Twin Comanche, Dutchess.
One of the most interesting design concepts that I have seen is that the basic Bonanza wing section has been used in nearly the entire later Beech line. You can see it in everything from the Bonanza, Baron, King Air and the 1900.
Oh well, so much for discussion on the Aztec!