I prefer the heavy old iron.
The good:
-it has all the crank handles
-none of the levers look broken/bent/abused
-it's local to you and you have the power, space and a trailer
-it looks like it has a coolant pump in the reservoir base (the switch on the left side)
-it only looks dirty not rusty, it likely only needs a good cleaning and lube
-since you can go in person, it's fairly easy to inspect the dovetails.
The arbour support is missing, but could be fabricated.
It likely has a B&S #11 spindle taper, those can be a little tough to find, but not impossible....just keep looking.
Please do not underestimate what the thing weights. Sure they can load it with a fork lift, but you need to unload it safely.
When I got mine(older and rougher than the one shown above) I emailed Cincinnati and they advised on where to find the serial number. When I got them the serial number they could tell me when it was made, the total weight, what the taper was and what lubricants to use.
There are some Cincinnati manuals here:
http://www.hobby-machinist.com/resources/categories/cincinnati-except-grinders.30/
....and one for the 1-M specifically here:
http://www.hobby-machinist.com/resources/cincinnati-1m-pdf.2955/
Please let us know!
-brino