145 is more roomy. 122 is maybe more stylish.
Either case, find a rust free (near as possible) one. You can end up in restoration heck up to your neck in decisions about floor and panel replacement, not to mention bloody knuckles.
Drivetrains are entirely interchangeable. Rear axels are not, where there may be a consideration about rear disc brakes on earlier 122's.
Most mechanical parts are easy to find, at least on line.
Manual transmissions are eventually preferable, once you accept the facts about owning and daily driving an old volvo. Autos are fine if expectations of mileage and performance are not high.
Certain things always need to be done. Center driveshaft bearing replacement. Door stops break off. Common minor windsheld leaks. Heater fan in late 145's.
Interiors are going to be worn, unless totally babied. Easy (possible) to swap in 245 interiors to late 145's.

I have a 74 145 with 255k on the odometer, just pulled the engine and it shows only .001 wear in the cylinders, which is negligible. Suspension-wise, it really only needed lower balljoints. I felt lucky. The car was from Oregon.

Really the only issue is rust. They drive and ride great, get good mileage, and are cheap to insure.



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'74 145e T-5 'Orange Alert'