Looking for Answers about Patagonia Patagonia Puffball Bunting Suit 3 (Infants')?

The MEC Toaster Suit has significantly more insulation (240gm Hyperloft) than the Patagonia Puffball (100gm polyester) so offers a higher loft, better insulating suit.
The key difference between the suits (apart from insulation) is that the Puffball is reversible and has a single angled zip, whereas the Toaster Infant suit has a double angled zip. It also has internal gaiters and a more abrasion resistant nylon shell.

The Puffball suit does not have any convertible foot coverings, most likely to reduce bulk in the ankle area.

I pasted the answer from the similar question you posted on the Toaster suit:

My questions are: what type and warmth of sleeping bags will you be using for yourself? Are they warm enough for the conditions you will be camping in? Is there room for you son to sleep in the bag with you?

One idea (if your sleeping bags allow for it) is to zip the 2 adult bags together to make a "bed duvet" and have your son nestle in there with you. I would recommend bringing extra blankets (and a hat) too for added warmth and bundling.

Another option is to rent warmer adult bags from our Toronto, Ottawa or Barrie location. Most of the bags can be zipped together.

A concern with using the suit is it may not be comfortable and likely not as warm as having a human body for heat.

Well, it is made of synthetic materials and insulation. so it won't absorb as much water as some other materials would. That said, this is not a waterproof piece... It has a water-resistant coating on the outside, so light rain and snow will shed off, especially when the suit is new. But as the suit ages, the treatment will wear off and might need to be re-applied. Even with brand-new treatment, this is still not waterproof, so heavier rain will start to soak through.