Putting my initial reaction aside, I've heard the piece (admittedly only once so far so I haven't made my mind up about liking it), but it is going to be a stern test for the band. Okay, it may not be full of semi-quaver runs, clashing chords, complicated percussion parts etc., but it, as Howard rightly said in an earlier comment, it will test warm of sound, muscianship and intonation.
I've done a bit of background searching about 'Resurgam', and, not surprisingly as it sounds very 'hymn-like' in places, it's origin seems steeped in religious undertones, allowing the listener to contemplate the fact that what may appear to be pain and loss is often gain and victory in a spiritual sense. Even from death, 'I shall rise again'.'
To give some indication of how difficult it is likely to be, it was used as the test piece for the British Open in 1950, so played by Championship Section bands of the day. Despite usually being put off brass music such as this mainly down to it's age, I'm looking forward to working on this. I can only seeing it improving the band, particularly with our intonation.
I found the picture of Eric Ball here