I have 2 different brands, The first Years and a Safety 1st. I know what you mean about the base being too big. The First Years one I have the base is almost too big for the chair but it still fits and I'm able to make it nice and snug. I like both of them in different ways. They both are adjustable in height. The Safety 1st. is nice because it's a thicker and really durable plastic not flimsy at all BUT a huge pet peeve of mine is I can't push the chair all the way in under the table because it sits too high, so the chair sticks way out. The first years one is the one with the bigger base and it's just a little flimsy, it's a thin plastic and you can't take the buckles all the way off to wash, BUT you can put the tray on and off with one hand and it fits nicely under the table. So they each have their advantages.
They both are easy to clean but the Safety 1st is probablly easier to assemble and disassemble.

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