The reason I was asking is that the apache code and your NTPClient.java sample provide a lot a lot of features, most of the them only logged to the console. I'm sure you do not really need all those values so in my eyes it is a bit oversized relying on that library if you only want to get the current time.
Deep inside, the apache library uses the same way to get actual time as the simple SPSntp lib. So the results and stability should be the same.
Apart from the above I'll take your request and implement the option to set an an own/preffered time server. Just be patient...
... done...
specci48