You talking about their Yaqui slide? It's a knock-off of the Galco, which is a variation of the Milt Sparks, which he copied from one that Jeff Cooper saw in El Salvador.
El Paso makes fine quality merchandise. I am not a fan of many of their designs. Their specialty is antique designs, and modern designs are better, for practical purposes, than antique designs. Many of their "replica" holsters have uncovered triggers, and covered grips straps, which is the reverse of what they should be, but they are historically accurate. Their modern designs are all copied from others, but there is nothing wrong with that. They are holster makers, not holster designers. If they make a copy of a design that you like, you can be sure it will be high quality leather and craftsmanship.
If you had to choose between an El Paso Yaqui and a Galco Yaqui, you could base your choice on ready availability and price.