We went a couple of years ago (girls of 6) – it is a pretty decent set-up and they do set the story up really well (ie, how the kiddies are transported to Lapland) and at the start (indoors) they even have heaters going to warm you up so when you walk out into ‘Lapland’ the cold hits you. When we went they had one bit where the kids get to help Santa build toys, one of them being a cuddly reindeer which you can then subsequently buy a version of in the shop which our two found magical to open on Christmas Morning (ie believing it was the toy they actually made).
Also, you send info to Santa about your children up front so when they see him he already knows things about them.
All in all I would rather not do this stuff as it IS very commercial but my wife wanted to do real Lapland so this was a financially preferable option and all in all it wasn’t too bad.
There is also a really big garden centre nearby that has a big Christmas section so you can browse in there too and start to get really festive.