Just sharing ... my 3 bedroom doors are ordered from Siong Door.
If you go to those reno forums you'd most likely heard of them, I guess younger generation taking over business tend to have more aggressive online presence, even for other trades (flowers, car tyres, you name it). Siong Door is pretty well known for group buys for their solid veneer doors deals with many of the new HDB BTOs.
Jay looks young actually, like some late 20s kid (yeah my age I can call him
"kid" 
). He's not always at the shop, if he isn't then you will be attended to by Pinay or ATB, and it's fine if you're just there for viewing, but if you need to discuss real business and / or you have special requirements you need to
cham siong with them, you'd want to speak to Jay directly ... the Pinays and ATB are very inflexible and hard to talk to some times.