I think it's different priorities. I'm trying to get the characters, sometimes at the expense of other gem items (I'm missing a few buildings but I can't tell since some aren't listed (I think BOG is one) and at least a dozen floats). I bought a few characters way back when (I can't remember which ones but it was back when I was trying to get the annoying ads to stop) and I try not to give them money for timed events. If I am going to buy one I'd prefer to get one that's part of the main storyline. I was missing 3 characters then got Boo as that big gift that was on the calendar a few months ago, just felt like I had enough gems to get Rex a few weeks ago, and I think I'm a long way away from getting Wall-E. (I have enough gems to get him, but if I do then I will be worried when the next event happens, so I'm likely to wait). With the characters (unlike the floats and the buildings, concessions, etc.) you get some gems back for completing the set, so that helps.