I dislike trijicon. Every duty pistol I have been issued has had them. Dust gets under the glass where they are painted white. At night they are fine. In the daytime it can be a pain in the butt, depending on lighting. BTW I haven't had one on xd's, have had them on sigs and glocks. Sig uses same sight as xd, glocks look pretty similar.
The XS big dot doesn't have a rear tritium. But it is great for fast acquisition. Not great for precision shooting at night. Group sizes will usually drop in the day as well but not by as much as one would think. I do like it for conceal carry though. I do not have one on an xd, it's on a glock 27. For a straight up personal defense pistol it is the best tritium option I have found.
The truglo TFO are the ones I like best for a pistol that doubles as CC and target. They look a little brittle, but have held up well for me with CC. I like the hi viz daylight part of it. You can really shrink the groups as apposed to the factory white dots. I think it is just that they stand out very well so you are able to focus on the target instead of the front sight and target. Kind of reminds me of a holo sight dot. As long as you have the gun lined up right the bullet pretty well hits where the dot is. You really don't focus on the dot. It just falls where you want the bullet to go. I have the TFO on a xd45.
