The decision of which vehicle to purchase is a personal decision. Either you prefer one style or the other.

However, if you spend $12K on a W123, you pretty much need to keep it a garage queen. It's priced that way because of it's condition and mileage. Rack up some miles on it and the value will drop like a stone. Furthermore, it's difficult to maintain a vehicle in pristine condition as a daily driver.

If you want a W123 as a daily driver, find one with 125K on the clock in excellent condition and pay about $6K for it. Pocket the difference and enjoy the vehicle for almost the same amount of miles.