Ron,

I've heard only a very few instances documented Xtol failures for a good long time. Most reports I have read seemed to involve sloppy, undocumented or questionable techniques in mixing or storage.

For whatever its worth I've used Xtol for 6-7 years with no trouble at all, totalling around 20-25 5 liter packs.
I am however extremely careful how I mix, handle and store all my chemicals.

I think if you follow the package directions explicitly (and maybe add a few precautions) you will not have any problems. Start with good water (I suggest distilled water) mix at proper temperature, wait for the first part to dissolve completely, don't whip air into the solution and use full, airtight storage (glass bottles with no air space) and always use plenty of stock solution.

I have several fresh packs of Xtol here now and no thoughts at all about changing to anything else.