I like niches because they're more substantial and hold more stuff.

Niche - I don't want anything sticking out into the space other than shower head and control.

Another vote for niche. It adds a design element to play with and more functional I think.

I agree, and they're more sturdy. The shelfs are screwed in and tend to sag.

One advantage of the shelves is that they don't collect water and thus mildew.

I really like the niches, and like my Recess-It 1419. It is a pre-made piece that recesses in the wall between the studs that the tiler puts in before he/she tiles over. So, it can't leak. Also, the bottom is slightly tilted downward to encourage drainage so that it doesn't get scummy. I also really like the shelf you can get for it so you have a low-height area for you soap, and above a taller area for your shampoo bottles. I think they are a neater look than a bench, but I still have a low tiny corner unit to prop up a leg when shaving. Sorry I don't know how to post a link to the Recess-It, but I'm sure you can easily find it with a search. They make several different sizes. Tilers can make their own niches, but you will probably save on their tile what you will pay for the pre-made one.

Our tiler made a corner shelf out of our natural stone tile. It looks really cool and blends into the design as it is the exact same stone as the wall. Our shower is quite large, and these shelves are above a built in bench. They have been great, and I think a niche would make me worry about cleanliness and mold growth. I would not want any other shelf that wasn't made of te exact same material as the wall tile around it.

Sorry this is so long... but using *both* worked well in many ways for us; I "had" to explain it (1st post: can I put pix in these msgs?).

We just did both bathrooms: a 3/4 bath & a full bath. We had our tile guy do the full bath (3-wall semi-enclosed tub w/ shower in tub enclosure) with 2 porcelain shelves in the front corner (at the shower wall). The smaller bathroom has a fully-tiled shower stall, the walls are in white straight-stacked subway tile; we had them build a seat at the back corner. The seat & floor are 1" rainforest green marble. It's my 16-yr-old daughter's shower (lots of STUFF), so we had him tile in *2* porcelain shelves (1 smaller, 1 a little larger 18" below it). On the side wall opp the shower wall: a framed-in niche (betw studs)-- the inner perimeter is lined w/ the marble.

It looks awesome; plain white shower walls (straight-stacked subway tiles ) with that gorgeous green marble on the shower seat/ floor. No borders on the tile walls, but the inset, in that marble... very practical AND beautiful. We're not finished in there yet, but the hole where the medicine chest was (we moved the toilet & vanity) is now a niche over the toilet; it will have the marble trim... a piece of 3-d art will go there. The shower is approx 42"x42"; but it's way less crowded than my description sounds. Plus her various potions are neatly stashed, no bottles on the shower floor, no telescoping floor-ceiling racks, nothing hanging off the showerhead... (The shelves in both rooms are in the corners of the enclosures that are hidden, so it all worked very well. The tub surround was too open so we skipped the niche in there; it would've ruined the clean modernist lines of the tiled surround.