The larger (Milwaukee 2645-20 18volt) came in a kit I bought about a year ago. It came with a circular saw, sawzall, light, couple of drill etc. I have been very happy with everything that came in this kit. The larger jig saw is a bear. Its big, heavy and will cut through anything. I recently used it to cut a round opening in my roof for a bathroom exhaust. Cut right through the sheathing, shingles and roofing nails like butta... a job normally reserved for the sawzall. There is enough weight to this thing that it didn't chatter and jump all over the place while cutting the roof. I thought it would be handy when I bought it to do shop related tasks. Well, yes and no. Some things its good for, but finessing a cut is not one of them. Here the Bosch jigsaw wins... until now.
Milwaukee recently came out with the M12 model jigsaw. It uses the smaller 12volt stick batteries their other cordless drills use (at this point I think I have just about all of them). Seeing that I'm swimming in M12 batteries... I bought the tool only.
Its light, nimble and has plenty of power. It has an LED battery charge status on the side and an LED guide light. It also has a clear splinter insert and scuff pad for the base. It has now rendered the Bosch useless.
Its the perfect saw for getting into tricky cuts or repairs on cabinets piled up in the shop without draping a cord over everything. If your in the market for a jigsaw, forego the corded ones. You'll never look back.
Get the larger one if your dealing with heavier jobs... cutting scrolls in framing for pergola's etc. For cutting lighter 3/4" material in the shop or on the jobsite... the smaller, lighter M12 version is the ticket.