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.

How about just the bench and getting a great basket or tray (that drains) and putting your products in it? That way you can get both. This might work especially if the bench is at least partly shielded from view from outside, if you care about your products being out in the open. The niches are useful but they do take some extra cleaning and I have to say that I don't love them. (there have been threads on the value of niches--people have definite views!) The bench is a really nice look. I am not sure how much anyone really uses it to sit (maybe as I age, I will sing a different tune) but it is nice to prop up the leg when washing or shaving.

Tempered glass is really only susceptible to shattering if it's hit by something that can scratch or chip the edge glass. Most items in a shower are soft; plastic bottles, elbows, even boney elbows. Metal shower heads can be hard, but they usually don't have much mass behind them, so they'll usually just deflect off the shelf if they collide. Though I don't have glass in my own showers, I've installed plenty of glass shelves in houses. In showers, medicine cabinets, and the one that always makes me cringe: in kitchen cabinets. I give the owners of the homes I've built an annual call. No one has ever told me about a broken shelf. Every few years one of the glass shops has a "let's break glass" demonstration. I was placing an order at the shop several years ago when they had a demonstration. I stuck around to watch, it's pretty amazing how much abuse tempered glass can take. I'm not scared of using tempered glass, but I respect that it still is glass.

I would put the niche on the right wall, even un-centered, rather than under the window. The size you need might depend on just how much soap / shampoo your family uses. I love niches when properly waterproofed, but I wouldn't want them to be the focal point of a shower. Instead let your window be the centerpiece and tuck the functional niche on the side like you'd planned. Glass shelves in a shower, especially one used by children, seems like a bad idea. You don't want someone accidentally breaking or even slipping and grabbing a glass shelf. A niche is awesome because it's tucked out of the way but still provides ample storage.