In all my Blockland life... I've only been in 1 clan.
That was also a LONG time ago.
The clan is long dead and I have no plans on joining a new one.
I don't really see a point in a clan, however, if you like to actively work along side a group of people then maybe you could try it out.
There are quite a few clans that don't actually work together though, instead use it to boast. This defeats the real purpose for a clan.