Better is a judgment call.
Catching an exception is a much slower operation than testing for the condition and avoiding the exception entirely. However, unless you are going to encounter a large number of exceptions, the performance difference is simply not important.
It is hard too imagine a case where you would get large numbers of path too long errors, unless you are trying to do something where are copying or moving tree into a directory node that is already deep. In which case, you are probably better off to test everthing up front so you don't create a large slow operation that will fail in the middle.
However, a hard-coded 260 is a bad idea anyway as this previous answer shows.
There is no built-in windows function that gives the real answer for a given system, but you could simply determine the answer by trial and error (maybe a binary search) on the user system before starting your operations.
However, if you read the article I referenced, you will see that you can easily create longer paths in a program than will work well in windows. Windows explorer has problems once you reach 255 characters, so long story short, I would recommend a limit of 255 at most if you have any choice in the matter.