I have had Tru Glo's,Metropro's,Glock NS's.A friend let me try his Heinie Straight Eights and they'll be my next.I like them best.Of the first three mentioned the Glock Night Sights seemed brightest when new.
My new G-21 came with factory Glock NS. I called Glock and asked them who made them and was told that Glock makes the sights and Meprolight puts the vials in. I like the Glock NS. I also have Meps on my CZ. On my Sigs I have Trijicons. The meps seem to have bigger dots so I will have to say I like them a little more. JR
I have Trijicons on a old Colt Commander and on my "new" G34. I recently returned my Colt slide to Trijicon to have the 12 year old vials replaced. $54 for all three tritium vials is not too bad and when it comes back, there should be no sighting adjustments required. Something to consider...they DO go dim after a few years.
I have Ameriglo Pro I-Dot Operators on my G23 and G32 and really like them. I also bought 2 sets of Pro Operators, but haven't installed them yet. The Pro I-Dot has a single vial rear like a Heinie, but without the white outline on the rear sight. The regular Operators are 2-dot rear without the outline. I have XS Big Dots on my M&P 45's, but did not care for the supplied rear sight. I changed them for a Warren Tactical rear and have had better results. YMMV as I am 49 and wear progressive bi-focals.
I have 24/7 Big Dot on my G17, Tru Glo on my G19, Trijicon on my G22, AmeriGlo I Dot Operators on my G20, Meprolights on my G26, I like the 24/7 Big Dots and Meprolights best. The 24/7 are faster to aquire a good sight picture, but the meprolights are the same size, height as the original Glock sights. Most of the aftermarket night sights have a much taller than stock, front blade sight, creating the possibility of snagging the front blade on your holster while drawing out. The AmeriGlo I Dots are good too, but not as fast as the 27/7 and the front blade is a good bit taller than stock.