I am a fan of the XT60's but the 30 are nice too with less size. I did a bunch of soldering a couple weeks ago and one thing I did was set a plane and some LiPo's for 30's. That said, there is a lot that centers around 60's. Therefore I also made an adapter to be ready for whatever.
Bulky parts can be annoying from time to time. Some planes have small areas for the LiPo's and bulkiness can make hatches prone to flying off. By the way, battery straps are a very good idea too.