It would be real nice if they combined the features of both models into one.
In considering your smoker: 1. an insert helps in keeping it lit and burning as well as in cleaning. 2. The taller the stack the more fuel it will hold, the longer you can go without refilling (important if working more than 8-10 hives), and easier to stay lit. 3. The shield keeps the fingers protected when not wearing gloves. 4. The guard gives air space around the hotbox, a nice safety feature. 5. A hook under the spout lets the beekeeper hang the smoker onto the side of the hive.
Some beekeepers swear the domed top helps keep the smoker lit better, others argue to opposite, to me it's a wash, a novice is going to have lit smoker problems anyway.
Buy the smoker that gives you the most of the above features in the same unit then buy it. If you can see yourself with more than a dozen hives down the road, definitely get the larger, taller, unit.