While it's 100% okay for everyone to have opinions about other groups, let's keep in mind that the 405th is not about bashing other groups and we have a lot of 501st members here in the 405th, including myself.
Technically, the 405th may have that many accounts registered on the forum but the number of active members who are part of Regiments is relatively small number as in under 1,000 would be my stab in the dark. According to our last census in October, the 501st has 8441 active members and 662 on reserve. That isn't counting the number of inactive or retired members.
Let's also keep in mind that lots of people here also build kits and there is absolutely nothing wrong with that. It doesn't make someone any less of a costumer or builder. The skill levels in every group vary widely and all are encouraged to continue on whatever path it is that they enjoy the most.