I tried an aluminum bottle and hated it. I wanted to get away from the plastic tasting water.

Two issues sent me back to my old reliable plastic bottles.
1] Metal bottle dont collapse when you drink from them so you can not get much water out in one shot. The best way to drink was to blow into the bottle and drink from the resulting pressure in the bottle. Pretty dysfunctional.

2] They rattle in the bottle cages. Not a little bit, but every grain in the road sent out noise from the bottle. Tried bending cages and eveything else to no avail. In the end, this is why I ditched them.

I've had my current 2 plastic bottles for 2 or 3 years so I think the enviro impact is pretty much nil.