The Disney Parks dresses are different than the
Disney Store dresses. Both are good quality dresses, but often the Disney parks dresses are prettier and better quality. It just depends on the dress. They change out the styles and now and then one of the places has a dud- or one of the versions will be scratchy and the other not. We have had a few times where we have preferred the Disney Store version and several times where we far preferred the parks version. DD is 8 now, so she is mostly over the Princess dress up other than Anna and Elsa, and Halloween, but from ages 2 to 5 she wore those dresses about every day and we had a bunch from both the Disney Store and the parks.
I actually much prefer to buy the more expensive dress for a 2 year old that is going to wear it every day and get your money's worth out of it, than for a 7 or 8 year old who will wear it at WDW and DL, and maybe once or twice at home and be done with it. As DD got older and wore them less often, I cringed spending the Disney parks/store prices, where when she was young and wore it all the time it didn't phase me (much

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We were at
Disneyland last week and the Cinderella parks dress right now is absolutely gorgeous. It is the prettiest Cinderella dress we have seen in years. Cinderella is DD's favorite and we have had several disney store and disney parks Cinderella dresses, so we always pay attention to that one even though she is out of the dress up all the time phase. It was so pretty that I was a little sad that DD isn't into wearing the dresses all the time anymore. I don't recall what the current parks Merida dress looks like, I don't think we paid much attention to it. The Cinderella one always gets our attention because at age 2, she actually wore a Disney Store Cinderella dress every day for a year until it was ragged, tattered, stained, and she had outgrown it until she could no longer squeeze her body into it. We had a rule that it was only worn at the house, and if we went anywhere she had to wear real clothes, and the only time she wore anything other than that dress was to bed and if we left the house. The minute we got home it went back on.
Both the Disney store and parks dresses wash suprisingly well. We have never had any issues with putting them in the washing machine on the gentle or hand wash cycles, and then hanging them to dry. Other than the one dress that DD wore every single day all day when she was 2, most of hers looked practically new by the time she outgrew them even though she wore them a lot.