Definitely have to agree with a studio being too small for a family w/ 2 young kids. We also have 2 young kids and loved the space of a 2bdrm unit. Recently we spent just one night in a 1bdrm T/S and it felt cramped.
I wanted to also mention that some T/S have lockoffs, meaning, it's a 2 or 3 bdrm unit, but there's an extra door and you can lockoff a studio or 1bdrm portion. If that's the case, then both portions would trade, enabling you to get two weeks of vacation as opposed to one.
Also, most T/S have the 'every other year' option instead of annual usage. So, if you can find a T/S that has lockoff capability, and then purchase EOY, you can essentially vacation EVERY year. However, your maintenance fees will be half because you technically own EOY. For example, if the T/S maint fee for annual owners is $800, then for those who own EOY, it's roughly half. Additionally, if your T/S is high demand and you purchase in a high demand (red) season, the exchange company may give you a bonus THIRD week when you deposit. This gives you THREE weeks of vacation instead of one! This is what we have - and it's worked out great for us.