I agree with your tradesmen. I MUCH prefer to build my own. Then IU can make then any size I wish, and locate them how I wish, so as to make sure they fall into the coursing of the tile. I've got several Laticrete preformed niches that were given to me when their system first came out. Since that time, I've installed probably 2 dozen showers. I've still got the niches.

Nuff said.

DH built all three of ours (three different bathrooms) and was able to customize them, as Bill says. He even adjusted them after they were installed, prior to being tiled-in (so the tile would line up optimally).

I agree with Bill and cat mom and would also add that most of the preformed niches I've seen are pretty small. I really, really liked being able to customize mine to the perfect sizes for my Costco bottles.

Thanks for the input. Wouldn't the prefabicated niche would be more waterproof and less likely to damage over time? I totally understand that we would have more flexibility to customize.
Thanks!

DH built the niches in-place, using 2x4's or whatever boards he used for framing them out. Then the cement board went in (Hardibacker). He then coated the tub and shower surrounds with Hydroban (3 coats) brush or roll-on waterproofing membrane, including the niches. When he had to "move" one (or two) of the niches, he re-coated the niches with more Hydroban.