I've got two sets of Trijicons on my GLOCKs, they're allright. I used to have a G19 and G23 with Meps, they were okay, also.
I got the Trijicons mainly becuase they were on sale, but if I had to pay full price I'd get some Meps from Glockmeister.
The differences between the two are minor. First, Trijicon gives a bit more sharper dot than Meps. It might have something to do with Meprolight having some plastic covering the vials. Also, Meps uses a white plastic for the outlines on their sights; Trijicon uses some sort of compound.
It's really personal preference. I think meps will be easier overall because their dots are bigger in daylight and when it's dark they glow bright still (though a little blurred compared to Trijicon).
My $0.02 (which after taxes are near worthless).