I think it would depend on his weight and how much use you'll get out of that seat. Will it only last him a year if he's on the bigger side or can you get at least 2 years out of it? Do you plan to have more children, meaning it will be a good investment for the future? Does it do anything else, like convert to a high back booster? I'm a big ERF fan and we did exactly this when our daughter was a year - pooled all her birthday and Christmas money - and bought her ERF seat, which we love. Our daughter is small, so we'll get 3-3.5 years of use out of it with her (until she's 4-4.5), and we plan to have another baby, who will grow into it right about when she grows out of it. Plus it also converts to a high back booster when FF, so we can literally use it up to the full 10 years that the manufacturer will guarantee it. For us, that was a good investment. I think though in your case you need to weigh up the cost against how much use you'll really get out of it. In an ideal world, we'd say that safety doesn't have a cost too high, but you have to be practical at the same time.