I've gone back and forth with this, a lot this year. As mentioned in another thread, I sweat buckets. So it would seem a bladder would be better for me, since mine hold 100oz in theory. Well...
If I can't see how much I'm drinking, I drink too little. So technically it may be easier to drink from a bladder. But it turns out I pretty much need to pull a mouthful of water out every minute to get enough, which is impractical. If I try to draw out as much as I can to make it more like every 5 minutes, it ends up leaving me short of breath. The faster flow of the bottle ends up working out a lot better for me. Plus the whole out-of-balance thing goes away in no time. Putting the bottle back is the tougher part. Just pick a part of trail you think is safe, then look down if you need to. If you try to half-look and half-watch the trail, you'll just end up sloppy and possibly out of control.
As Heythorps mentions, it's messy with non-water in a bladder. So I've gone to a slightly absurd sounding method of having one bottle on the bike, and 2 in the pack. So I don't get away from having the pack on. This is obviously a comment on a roughly 3 hour ride, with 1 bottle per hour. Every hour I make sure I've drained the bottle and I stop for about a minute, pull out a new bottle, and reload. I find the 60 seconds less of an inconvenience than the constant sipping of the bladder.
My bike has a second spot you can mount a cage, on the underside of the down tube, which seems an absurd place to put a cage. I've ripped the zip-ties which hold my shifter cable in place twice this year by kicking up rocks. Also have a few nasty scars on the rock ring. I can't imagine that being a good spot. But I may give it a whirl for the proverbial sh!ts and giggles. (As an aside test, I wonder if shit gets turned into ****).
As for cages, I've always bought the junk ones and they break from wear every few years. If I crash that catastrophically, they usually just bend. I find it a non-issue. Don't waste your money on this particular bell and/or whistle, IMO.
This is a huge YMMV area.