My husband and I are heavy in the research phase for our new tile shower. We have also talked to a few contractors in case we decide to send the job their way. However, we keep getting contradicting information from all angles. A lot of the information we are coming across is from the manufacturers, which I suspect is a little biased. Additionally, we are trying to figure out which contractor is giving us the best option, not just the quickest so they can move on to the next job.

We are looking to replace our standard 4 ft. x 3 ft. shower. We would be doing 1-2 recessed shelves in the space and our drain is located in the center. We are impartial to a tile floor or a standard base. We like the look of a tile floor, but ultimately want to pick function over design on that aspect, especially since we are replacing our shower because of cracks in our existing shower floor.
Basically, our biggest deciding factor is which method will deliver us the best durability and water-proofing factors. While we don't want to break the bank doing this project, it is one that we definitely want to do right the first time. Here are the options we have researched/been suggested by contractors:

1) Wedi system

2) Kerdi system

3) Redi tile shower pan with water-proofed concrete boards (red guard)

4) Koehler cast-iron shower pan with water-proofed concrete boards (red guard)

I would love to hear your thoughts and opinions based off of your own experiences.