Hi Jake...

Without stealing Larry's thread to answer what you read is probably true.
When the first retractable gear Cessna 337s rolled off the line there was a problem with the gear and pilots had to pry it down with a bar...Cessna soon fixed that.
The 337 like a lot of aircraft was underpowered, maybe not the military version but the civilian aircraft was...
It also had a noisy interior, you were in a small cabin between two engines...
The rear engine sometimes would overheat and the aircraft just did not have enough power to takeoff on one engine and taking off on one engine was just not recommended.
That is why you had to monitor the engine guages because if the rear engine quit prior to getting into the air you had to act quickly. With the front engine you could see the prop turning where as the rear engine you could not.
Not sure if someone added mirrors to the aircraft to watch the rear prop or not.
It was an expensive aircraft to maintain but if everything was working right you could ignore the noise with good headsets and the aircraft was a wonderful machine to fly, one of Cessna's best...
Only have heard of one being on floats and that was done here in Canada, do not know what ever came of the modification or the idea...