Hi wazzbat, I can see that you're in a quandary and you've now reached a cross road. Let's go through the options. The model 33 was built from 1960 and is now (depending on the build date) almost 50 years old. The bearings, if still original, will need to be replaced, and the roller drum and cutter clutches will most probably need attention.
I am not a big fan of Tecumseh engines, the company has gone down the gurgler and spare parts will be hard to get in future; so an engine replacement will be on the horizon at some stage.
The cylinder reel, depending on how many times it has been spin ground and sharpened, may not have much life in it and have to be replaced....These, if available, are expensive.
If you had the time, money and expertise, all these probs can be resolved and it could be restored to original condition.It all depends on what you feel is
appropriate for you.To give it the "Deviosi" treatment would cost serious dollars.
If you decided to sell it, it would be better to do so whilst in going order.
Now to a Model 45, these were manufactured from 1968 and have only just ceased production (as the Rover 45), but there is a "knock-off" being produced in China as the "Star" and also one manufactured in South Africa as a "Rover" which from all reports, is of good build quality.
All parts are readily available. You can even purchase a brand new chassis if required. Catchers are being manufactured and sold on e-bay. Decals and stickers are now available.
It comes with a sturdy Briggs and Stratton engine, parts are available and are fixable (with expertise from members on this forum)if needed.
You have a choice of a 17" or 20" cutting width in the Model 45. They are relatively easy to work on, and well maintained will give you hours of mowing pleasure.
Hoping that this has given you food for thought.
Best wishes and please let us know your decision,