The plastic bottles of varying types are lighter than the equivalent metal canteens, BUT in the winter, there is the possibility that your canteen might freeze.  One can heat a frozen canteen in a pot of water, as long as one has a pot sufficiently large enough to do so.  If one is winter camping, one ought to have a fairly large pot, one of whose uses is to melt snow tightly packed into it.  That's one of the reasons why the GI Arctic cooking kits have large pots: to melt snow, and heat up metal canteens.  OTOH, the metal canteens can be set directly on a stove/coals, and so the pot is not necessary.

Safety note:  If heating any canteen, make SURE the cap is loosened sufficiently so that pressure cannot build-up within the heated canteen, lest a rupture occur.  You wouldn't heat a sealed can of food, so don't heat a sealed canteen.

The only point I would add is that if wearing the canteen on one's body, a number of users report that they are annoyed by the canteen moving about--usually in a horizontal plane-- when performing strenuous activity.  IOW, the canteen/water bottle shakes side-to-side in its' holder.  Apparently, this occurs no matter the type of water bottle/canteen construction, but it becomes worse when using the very flimsy commercial water bottles, intended for single use, which add nothing to the stability of water bottle holders, unless completely full.   Some holders are better than others, so look carefully at their design, and try to see if their construction is resistant to lateral motion of the bottle/canteen.

Your metal GI canteen, if installed into a modern MOLLE Canteen/Utility pouch, is not at all a bad alternative.  For example, the canteen is intended to nest into a canteen cup, and the Mil also made a stove that nested onto the new-style canteen cup that worked with heat tabs.  Add a canteen cup cover (available commercially), and you have a pretty decent rig for winter.  Replace the metal canteen with an Oasis or GI plastic canteen for non-freezing use.  The GI plastic canteen often has a drinking port on the cap that can be used in conjunction with a gas mask, if that is of interest.

Your call, but I will NOT use any sort of food/water gear unless it is made by a respected and well-known manufacturer.  NO Chicom bladders, water bottles/canteens, or cooking/eating gear for me.  YMMV. 

Source is an Israeli mfr, with US distributor(s).  Nice products, but pricey.  Their hose fittings accept Camelbak accessories and vice versa, which is a huge plus all around.  I have heard quibbles about some types of Source mouthpieces (there are two), but the Source UTA device is very clever and well-worth the price.  In similar manner, Camelbak offers useful accessories that Source does not.

If one regularly does preventative maintenance on one's bladders, the advantage of opening up the top of the bladder in order to scour out the inside of the bladder disappears.  Of course, this entails using nothing but pure water inside the bladder, and cleaning the bladder and hose with a 10% bleach/water solution weekly at the least.  If you are an athlete, and find energy drinks of value, then the open-the-top bladders OR the newer Camelbak Antidote bladders with wide neck openings might suit you best.  The same advice goes for drinking tube cleaning.  Use only water, clean it often, and you are unlikely to need a tube brush.