Me! I've been to both and several times.
We think Disney is fab, great fun... Love the parades, shows... Big thunder mountain is outstanding as is ratatouille.
But it has a more circus atmosphere... Bright lights.... We had an annual pass and will definitely go back when the new areas are built.
Efteling is incredibly atmospheric. It's far more beautiful over all. You don't feel its as theme park in the same way as Disney. It's in a natural wooded setting so just walking around is enjoyable.
The fairy tale wood is exquisite. Watching my young dc run to each new tableaux was highlight of their childhood for me. Its endless and each one is different, some are interactive, some still like Tom thumbs giant but he snores and Tom runs up and down.. Some you watch in scenes...
Each one is different and beautifully done.
In terms of what to do instead of rides, apart from the the wood which can take all day if you want it too... There's a large square full of old rides, about 3 carousels, swing chair rides... There are far more decent and large play areas. We felt v frustrated by lack of proper spacious large play areas at Disney.
You can drink in park unlike Disney. I enjoyed sitting in white horse plein (Square with old rides) glass of prosecco and dc could run off and I could see them...
Land of the laffs is great fun with loads of houses to run in and out of, rope bridges... Rides.... Stepping stones and pond.
Dream flight (drumvulcht) is gorgeous. Similar in style to Peter pan but better... Longer and with more going on.
The food is much nicer and more variety.
The accommodation is so much nicer. At Disney the 'lake' is huge man made surrounded by concrete and nothing in or around it! Very corporate.
At efteling in my favourite accmd area... The lake is large enough but natural with ducks, reeds, trees around it and in the middle... The sand man's castle.
It has very cosy feel and lots of play areas. All themed really cosily.
I def prefer Bosrijk. It oozes charm and cosyness and magic. (as oppose to looshcne land and the main hotel which is in totally diff area of park unless staying in themed suite)
Unfortunately I can't think of a ride I like as much as btm. Possibly George and dragon...
I have not been for a while and we all miss it. We are going to try winter efteling this year and a new show everyone is raving about called caro based on carousel.
Otherwise my favourite time in on summer nights in July /August as they lay on extra entertainment and park open later.