I own both the MSR and the platypus bags. the MSR is definately a bit more durable - the platy is lighter. Both have toys and gadgets to stick on the end. The MSR with a wide mouth can be a bit easier to fill, but not really by a lot and most of the time I end up dipping a cup or pot to fill them anyway.

I usually end up taking the platypus (usually two 2l or a 2l and 3l bag), because they are lighter - I can carry two platy's for less weight than the MSR. this means that if one does get a hole in it I don't have a problem. I normally only carry a litre of water in one, with the suck tube on it. The other is empty normally with just a regular lid - I use it to grab a big pile of camp water at night, or for loading up on water if I'm going to camp where there isn't any.