I should qualify that my statement is subjective (without hard data to back it up), but here in Nashville, TN, where many music publishing companies used DAT as a storage media type for their catalogs, has been quite a problem. The primary problems that we have seen are incompatibility between players, and increasing error rates as the tapes age on the shelf.
If the tapes are used with regularity, that also seems to impact the shelf life.
Lastly, there are fewer and fewer machines available from manufacturers (we discontinued ours 3 years ago). There have been other posts with much more valid scientific data than mine, my post is based on the experiences that we have had within the music industry.
Hope this helps clarify.