I must admit that I also find Thirteen quite underrated; I enjoy it a lot when I visit Alton Towers! It's definitely not my favourite coaster by any means, but it's probably my favourite family coaster I've done! I find it really smooth with a really twisty, dynamic layout and many exciting moments for a family coaster, especially in the backwards portion of the ride! Dependent on where you sit, I even sometimes find myself getting some nice floater airtime in portions of the ride!
Admittedly, Thirteen is not quite my favourite coaster at Alton Towers within the 1.2m height restriction bracket (that would go to Wicker Man, but I'd class that as more of a thrill ride than a family ride.), but I still find it to be a very fun family coaster, and I can certainly see why
@toofpikk loves it so much! (For clarity, Thirteen is my #24 out of 66 coasters, whereas Wicker Man is my #11.)
Controversially, as I mentioned in my post above, I do actually prefer Thirteen to Expedition Everest by a slim margin, despite Everest's far greater scale. While I admit that Everest has more in-depth theming than Thirteen, I find Thirteen to have a slightly more dynamic, exciting layout that just does more for me. If we're being nit picky, I also think that Thirteen flows slightly better as a coaster than Everest does; Thirteen goes into that drop track and sends the train backwards very quickly, whereas with Everest, you're waiting quite a long time for the switch track to do its thing. Both are brilliant family coasters, however, and the difference between the two in my rankings isn't very big at all (Thirteen is #24, Everest is #25).