PSA: Be aware of what T100 means. This is a regulatory label required by the NRC, not a brightness rating. Companies are required to label their watches by the amount of tritium in the watch, and also need distribution licenses based this.
T25 means a watch has up to 25 milliecuries (mCi; unit of radioactivity), while T-100 or T means it has over 25 mCi but less than 100. Thus T-100 does not mean it's 4x as bright as a T25, or that it guarantees the watch has 4x as much tritium as a T25 one. If Armourlite wants to disclose how much tritium is in their watches, that'd buy some peace of mind. However, that still doesn't necessarily mean their tubes are "brighter". There could simply be more tubes, or more large/wider tubes.