Yes, I've heard of it. And no, it's not a good quality food. Actually, it is rather nasty junk

Here's a critique:
Iams Smart Puppy ingredients:
Chicken, Corn Meal, Ground Whole Grain Sorghum, Chicken By-Product Meal, Fish Meal (source of fish oil), Chicken Fat (preserved with mixed Tocopherols, a source of Vitamin E, and Citric Acid), Dried Beet Pulp (sugar removed), Natural Chicken Flavor, Dried Egg Product, Brewers Dried Yeast, Potassium Chloride, Salt, Vitamins (Vitamin E Supplement, Ascorbic Acid, Vitamin A Acetate, Calcium Pantothenate, Biotin, Thiamine Mononitrate (source of vitamin B1), Vitamin B12 Supplement, Niacin, Riboflavin Supplement (source of vitamin B2), Inositol, Pyridoxine Hydrochloride (source of vitamin B6), Vitamin D3 Supplement, Folic Acid), Choline Chloride, Minerals (Ferrous Sulfate, Zinc Oxide, Manganese Sulfate, Copper Sulfate, Manganous Oxide, Potassium Iodide, Cobalt Carbonate), DL-Methionine, Rosemary Extract
First thing you need to note is that all ingredients in dog food are required to be listed in order of their weight. So the higher up the ingredient list an item is, the more there is of it in the food. Kind of

Read on...
The first ingredient in the food is chicken. That's actually good. BUT: it is chicken inclusive of it's water content (as opposed to a dry meal). "Chicken" contains about 80% water - and once that is removed, as it must be to make kibble, this ingredient will end up weighing about 20% of what it does in the natural form. So is it
really the first ingredient? Highly unlikely
Now that would not be a problem at all if the second ingredient in the food were a meat meal. But it isn't. It is a grain. We can therefore conclude immediately that there is insufficient meat in the food (dogs are carnivores and need to eat food that is based on meat, not on grains - for which they have absolutely no evolved dietary need
at all)
The next ingredient is corn (actually the primary ingredient in the food). Corn is a very problematic ingredient in dog food - it is difficult to digest, of poor nutritional quality, and a very common cause of allergy problems. Many premium food manufacturers make a
selling point of not using this grain in their foods.
Next up is sorghum. That's fine, and a whole grain too. This is quite possibly the best ingredient in the food. Pity it's a grain and therefore largely irrelevant.
Chicken by-product meal is next. This is a seriously nasty thing to see in a dog food. By-products are not nice clean organ meats as some people imagine (those are useful elsewhere in the
human food chain, and certainly aren't wasted in cheap ingredients like by-products). Rather, these are items that are simply unusable in any other human or animal food products - including for condemned quality reasons (do an internet search on 4-D meats and you'll get a better idea).
The AFFCO (American Association of Feed Control Officals) definition of Chicken by-product meal is
"consists of the ground, rendered, clean parts of the carcass of slaughtered chicken, such as necks, feet, undeveloped eggs and intestines, exclusive of feathers, except in such amounts as might occur unavoidable in good processing practice." This is NOT good nutrition.
Next up is Fish meal. This is a potentially good ingredient. Unfortunately, it probably isn't. Fish destined for meal that is fished in US waters is
required to be treated with Ethoxyquin. Ethoxyquin is a chemical preservative that is banned from the human food chain because it is
carcinogenic. You will not see ethoxyquin in fish meal listed as a preservative on dog food labels because the manufacturer is only required to list those things they add to the ingredients themselves, not things added before they got it. When there is fish meal used in dog food, you therefore need to
check that the food manufacturer guarantees to be using ethoxyquin-free sources (ie. farmed fish). Iams provides no such guarantee. It is therefore a virtual certainty that this food contains ethoxyquin (ie. is carcinogenic).
The last ingredient I'd complain about is beet pulp. Beet pulp is a controversial ingredient in dog food that some manufacturers claim is a good source of fibre; others claim it is added to dog food to slow down the decomposition of rancid fats and causes stress to the dog's liver and kidneys in the process. Whichever version you prefer, beet pulp is certainly a waste product being the residue of sugar beets after the extraction of sugar. It is also an ingredient that happens to cause a lot of allergy and yeast infection problems for dogs.
Soo. That's the Iams. Not much in there that you'd want to deliberately feed to a dog

Certainly nothing that constitutes good nutrition for a puppy.
Switching to a better quality food is certainly a very good idea. There is some good information on how to choose a good quality dry dog food at
www.boxerworld.com/feeding No food can be better than the ingredients that go into it, and that page tells you what to look for, what to avoid, and why.
Some suggestions I'd make on good quality brands are: Canidae, Chicken Soup for the Dog Lover's Soul, Innova, Timberwolf Organics, Fromms Four Star, Merrick, Blue Buffalo, and Wellness. With the possible exception of Blue Buffalo, you are unlikely to find foods like that in big chain petstores (they prefer to sell the low quality foods they can shift in bulk). But feed stores and smaller petstores frequently carry them. With a quick internet search you would easily locate the manufacturers websites, most of which have store locators on them too.