The Andaman is lovely! We've just been for the February half-term week (stayed twice before when we were living in Asia and we've stayed at The Datai, too). No disco, only cabaret singer who stops before midnight every night - but the good restaurants are well away from that.
I'm suprised people found the food bland - the Malaysian/Indian restaurant in the rainforest, The Gulai House, is fab, and the Thai Pavilion at The Datai is fantastic, and will up the spice level according to your preference (you can eat at restaurants from either hotel and cross sign. The walk along the beach or through the rainforest before and after dinner is very relaxing.) The restaurants are expensive, though.
The Andaman is much better for children than The Datai. The pool area is very well laid out, with islands, bridges, a small slide and lots of shade. We love it when the monitor lizards swim across the pool and the kingfishers dive down for drinks. The children love seeing the monkeys at dusk, as well as the hornbills, sea eagles, butterflies, flying squirrels and colugos, crabs, fish swimming round your ankles at low tide....The guided evening and morning forest walks are well worth taking.
There is also now a kids' club at The Andaman, though we didn't use it (free, I think).
The spa is beautifully located and the beach is soft and sandy - beach toys available to borrow free of charge from the watersports kiosk.
We really couldn't recommend it highly enough.
Other friends in Asia also recommend Tanjung Rhu on Langkawi, but I haven't been.