Did the shrimp taste too "limey"? I tried another ceviche recipe calling for scallops and key lime juice and the pucker factor was too high for me. Maybe scallops are more pourous than shrimp or key lime juice is more tart.
If it's too limey, try boiling the shrimp for about a minute, then marinate for 3-4 hours and you'll be fine. I do use fresh-squeezed lime juice.