My glock has the standard fixed sights. I want to get night sights but not sure which ones. Are they hard to put on or should i pay the store to do it?
"Best" is subjective to each person.
I have Tijicons, Meprolights, XS, AmeriGlo, TruGlo TFO, on my GLOCKs.
My favorite is the AmeriGlo Pro Operator.
It all depends on what you are looking for.
Installation is not hard with the proper tools, many have installed the rear sights with a hammer and a punch, screw driver, dowel rod, ect.
But do you really want to "beat" an expensive night sight into the dovetail?
Up until last year the stock front GLOCK sight was pinned, and could easily be remove with a set of pliers. Now they are held like the aftermarket sights with a small hex head screw. Some companies furnish this nut driver with their night sight sets.