If you plan on having more kids in the next 2-3 years, look at getting the double trailer now. Your daughter can ride in the trailer consistently to roughly 5. After that they start to get too big and/or are able and willing to ride (i.e. the trailer is not as much of a necessity for family rides). They can still reasonably ride in the trailer until ~8 but the frequency should go down as they get older. Of course this is a generalization. The end idea is that if you are going to have more kids, get a double trailer now. You will not notice the expense over the next 7 years (assuming you have another child). We are on year 5 trailers and will be in them for another 5-6 years. Do I notice that $450 I spent, not one bit. Am I glad I did, you bet.
Another option is to go the used route. There are plenty of Burleys about. They do not discount as much as I think they should but they are cheaper.
Get the one that you think your daughter will be most comfortable in. The two of them likely roll about the same. They both have decent hitches. Transportability may be an issue for you (how small and how quick does it collapse). Enjoy whichever one you get.