You don't say what format! 4x5"? And there is a fundamental choice between the "old" f4.5 lenses and the much newer f6.1. I grew up with f4.5 Xenars, they are fine lenses, not so easy in 2006 to find in really good condition, the single coating I would say is not really an issue, flare suppression is good, macro contrast is medium, micro contrast (aka "sharpness") acceptable but not quite at modern standard, coverage of 210 f4.5 adequate for 5x7", ample for 4x5". I have several f4.5 Xenars, including a 135 mm which I had repolished and recoated (nice lens), an original later-model 150 mm (also good) and a 210 mm which is OK but a bit tired. In today's market it is easier (and not much more expensive) to find a Symmar convertible or even Symmar-S, which will probably be in better condition. The f6.1 210 mm is a different kettle of fish, micro and macro contrast right up to modern standards and a very nice compact lightweight design.
Regards,
David